Season 9
Episode 103

In the tenth season premiere, Penny’s family arrives for the wedding ceremony, including her anxiety-ridden mother, Susan (guest star KATEY SAGAL), her drug-dealing brother, Randall (guest star JAC...

The cast of The Big Bang Theory answers fan questions from Twitter.

Writer's Panel at the 2016 San Diego Comic-Con.

In the ninth season premiere, Penny struggles with Leonard’s confession that he kissed another girl while on the North Sea. After driving to Vegas, Penny must now decide whether she wants to go thr...

After Amy breaks up with Sheldon, he tries to retaliate by filming a special episode of “Fun with Flags.” Leonard, meanwhile, confronts the woman he kissed on the North Sea in an attempt to put Pen...

The guys’ science skills are put to the test when they get a flat tire during Leonard’s surprise bachelor party weekend in Mexico. Meanwhile, the girls force Penny to finally tell her family that s...

When Penny and Leonard announce they’re moving in together, Sheldon decides to revert back to 2003 – a simpler time before he met either of them. Meanwhile, Howard and Raj form a band to play at th...

When the guys take fencing lessons from Barry Kripke (recurring guest star JOHN ROSS BOWIE), Sheldon finds himself in an awkward position when Kripke expresses interest in Amy. Also, Stuart struggl...

In the midst of a nationwide helium shortage, Sheldon and Leonard take desperate measures to obtain the supplies they need on the black market. Meanwhile, Penny and Bernadette download a dating app...

While being interviewed for a documentary about Spock, Sheldon struggles to suppress his emotions about his recent break-up with Amy – leaving Leonard and Penny shocked to discover that Sheldon had...

With Amy out on a date with a mystery man, Sheldon enlists the help of Howard and Raj to find a new girlfriend by posting online. And when Amy is coy with the details about the guy she’s dating, Pe...

Sheldon and Amy try hanging out as friends when they spend Thanksgiving together at the Aquarium. Meanwhile, Howard reluctantly agrees to volunteer at the soup kitchen with Bernadette, Raj and Emil...

After driving Leonard and Penny crazy by his desperate attempts to remember the name of a song stuck in his head, Sheldon has a revelation when he realizes why. Then, despite their previously awkwa...

After more than five years of dating, Sheldon and Amy spend their first night together; while Leonard, Howard and Raj must decide who will take their extra Star Wars movie ticket. Recurring guest s...

Penny gets more than she bargained for when Leonard agrees to meet with a psychiatrist on her behalf. Sheldon and Raj collaborate on an astronomical discovery. Howard and Bernadette can’t believe w...

After having to deal with Sheldon being sick, Leonard, Penny and the gang try to treat themselves to a Sheldon free weekend.

Sheldon’s thrilled when his Meemaw (guest star JUNE SQUIBB) comes to visit, but his excitement quickly fades when she butts heads with Amy. Also, Raj meets a new girl (guest star ALESSANDRA TORRES...

Sheldon and Amy host a special live Valentine's Day episode of "Fun with Flags." While Leonard and Penny grapple with getting older, Howard and Bernadette find a surprise in their hot tub; and Raj ...

When the gang finds out about Bernadette’s pregnancy, they celebrate by singing karaoke. Meanwhile, Bernadette is concerned when Howard freaks out over her pregnancy announcement, as he’s convinced...

After more than nine years together, the gang finally celebrates Sheldon’s birthday with a few special guests on the 200th episode. CHRISTINE BARANSKI, SARA GILBERT and WIL WHEATON return and are j...

Leonard, Sheldon and Howard run into problems when they file for a patent for their infinite persistence gyroscope. Meanwhile, Penny, Amy and Bernadette give Raj dating advice after Emily reaches o...

When Sheldon’s laptop dies, it leads him to share a deep secret with Amy after she buys him a new one; Meanwhile, Raj sells out Leonard and Howard after they lie to their wives in order to attend a...

Sheldon spills a secret of Leonard’s when the two take a weekend cabin trip with Penny and Amy; Meanwhile Howard and Bernadeitte must draw the line when Raj goes overboard with pregnancy gifts.

When a small argument between Leonard and Sheldon erupts into a heated fight, everyone must take sides during a group get-together.

The gang goes to a wine bar and runs into Penny’s old boyfriend, Zack (recurring guest star BRIAN THOMAS SMITH); Bernadette gets stuck spending the evening with Sheldon when she can’t go wine tasti...

Sheldon hires Stuart to spend the day with Amy when he’d rather go to a movie screening. Also, Leonard’s mother, Beverly, comes to town and Penny struggles to make a connection with her.

Chaos ensues in the ninth season finale when Leonard’s recently divorced parents (special guest stars JUDD HIRSCH and CHRISTINE BARANSKI) and Sheldon’s devoutly religious mother come to town. Meanw...

The cast of The Big Bang Theory answers fan questions from Twitter.

Comic-Con Writer's Panel

The cast of The Big Bang Theory answers fan questions from Twitter

The stars and creative team of The Big Bang Theory celebrate a milestone, their 200th episode, featuring their best moments, behind the scenes footage of episode 200 and red carpet interviews from ...

The stars and creative team of The Big Bang Theory celebrate the recipients of the new "Big Bang Theory Scholarship" which awards students pursuing degrees in STEM fields, featuring behind the scen...

Leonard and Sheldon (series stars JOHNNY GALECKI and JIM PARSONS) are brilliant physicists – geniuses in the laboratory, but socially challenged everywhere else. Enter beautiful, street-smart neigh...

When Sheldon is forced to teach a class, Howard surprises everyone by taking it. Meanwhile, the tension between Penny and Bernadette gives Amy a chance to play both sides. Guest star REGINA KING re...

Howard is nervous when NASA asks him to throw out the first pitch at a Los Angeles Angels game for National Space Day. Also, Leonard and Penny try to prove Sheldon wrong after he claims that he and...

Raj’s honesty about his past comes back to bite him after his girlfriend, is cold to Penny. Meanwhile, the guys consider becoming part-owners in Stuart’s comic-book store.

Amy and Bernadette accuse Penny of being a “buzzkill” after she gets an email from work during their Vegas weekend. Meanwhile, the guys try to invent something cool, but only come up with new ways ...

Sheldon and Raj test whether they could survive a dark-matter research expedition in a salt mine by simulating the conditions in a steam tunnel deep underground. Meanwhile, Leonard and Penny seek a...

The guys try to help Penny out of an awkward work dilemma, when a smitten doctor shows up at her door after her flirtatious sales techniques work a little too well. Meanwhile, Amy and Bernadette ar...

When the gang recreates a high-school prom night on the roof of the guys’ apartment building, Sheldon feels pressure to participate in all the typical romantic traditions.

When Leonard gets minor surgery on his nose, Sheldon is the one in need of sympathy. Meanwhile, Raj’s parents’ impending divorce causes Howard and Bernadette to work on their own marriage.

While Sheldon says a tearful goodbye to the final installment of “Fun with Flags,” Leonard, Howard and Raj search for something significant in a dead professor’s research. And Bernadette is shocke...

Leonard and Howard turn to Raj for help in dealing with a work emergency when they nearly come to blows after blaming each other for a potential disaster at the university. Amy throws an authentic ...

When the guys finally agree to do something the girls like, it leads to a confrontation between Leonard and Sheldon.

Sheldon worries his comfortable lifestyle is preventing him from achieving scientific progress so he asks his friends to make him miserable.

After Leonard and Sheldon co-publish a physics paper, they must defend themselves against criticism from an online bully. Also, girls’ night finds Penny, Amy and Bernadette confronting embarrassing...

Howard receives some shocking news as everyone prepares for the reopening of Stuart’s comic book store. Penny teaches Sheldon how to “let it go” but can’t follow her own advice after she learns som...

When the gang hears about an experiment designed to make participants fall in love, Sheldon and Penny put it to the test as a joke. Meanwhile, Leonard, Amy, Raj and Emily spend the evening trying t...

A trip to the pet store ends in a fight when Amy learns that Sheldon has applied for a one-way mission to colonize Mars. Also, Leonard surprises Penny with a very “adult” purchase; and Raj is caugh...

Friction ensues when a magazine fails to mention Leonard in an article about the paper he co-wrote with Sheldon. And a blackout at Mrs. Wolowitz’s home leads to a final family dinner in her honor.

When Leonard and Sheldon are invited to speak at UC Berkeley, they take a detour to try to sneak on to George Lucas’s Skywalker Ranch to meet one of their idols. Back in Pasadena, Howard and Bernad...

When Sheldon and Amy build a blanket fort, they come to a big crossroads in their relationship. And Wolowitz is shocked when a man claiming to be his half-brother he never knew he had shows up at ...

When Raj is asked to create a message in case a NASA mission discovers alien life, the guys fight over what he should do. Meanwhile, Penny is torn between auditioning for a movie or keeping her suc...

Wolowitz questions his engineering abilities when he and Sheldon can’t get a drone to fly. Meanwhile, a canceled flight nearly prevents Leonard from giving the commencement address at his former hi...

Personalities collide and sparks fly when Sheldon and Leonard’s mothers (special guest stars LAURIE METCALF and CHRISTINE BARANSKI) finally meet. Meanwhile, Howard decides to “man up” and do his fa...

In the eighth season finale, Sheldon presses Leonard and Penny to choose a date for their wedding, while dealing with dramatic changes in his own relationship with Amy.

Series director Mark Cendrowsi takes the audience on a guided tour of the non-stop action he and the cast endure every week while filming The Big Bang Theory.

The Executive Producers, Writers and Cast reveal what's coming in Season 8.

A tribute in memory of the late Carol Ann Susi.

Gag Reel

Behind the scenes of Billy Bob Thornton’s
guest starring role.

A documentary about the search for the world's biggest BBT Superfans and their trip to LA to meet the cast and crew on set.

On the one-hour seventh season premiere, Sheldon and Penny bond in Leonard's absence, but it's Sheldon's feelings that are crushed when Leonard returns from the North Sea. Guest star REGINA KING re...

On the second part of the one-hour seventh season premiere, Raj gets consoled about his ex-girlfriend and Howard's relationship with his mother causes an unusual threat to his masculinity. KEVIN S...

When the entire gang competes in a cutthroat scavenger hunt designed by Raj that tests their science knowledge and street smarts, it brings out the best -- and worst -- in everyone.

After Amy ruins one of Sheldon's favorite movies -- Raiders of the Lost Ark -- he gets defensive, seeking revenge. Meanwhile, Leonard discovers a way to get Penny to do anything; and Raj and Stuart...

Sheldon must decide how much "Amy time" is too much after she takes a job at his university, and their relationship is put to the test. Meanwhile, Howard finds himself sleeping on Raj's couch aft...

Sheldon's latest scientific breakthrough makes him feel like a fraud -- and threatens to haunt him forever. Meanwhile, Howard's romantic gesture to Bernadette causes Penny to step up her game with...

Sheldon feels slighted when Professor Proton (recurring guest star BOB NEWHART) seeks advice from Leonard instead of him, and he seeks revenge by befriending a rival science TV host, BILL NYE (gues...

Leonard tries to keep Sheldon from overreacting when a past mistake comes to light, but Sheldon punishes Leonard by making him "walk a mile in his shoes." Meanwhile, Penny confronts Raj's ex-girlfr...

An upset Sheldon protests when the entire gang drags him to Mrs. Wolowitz's house for Thanksgiving. Meanwhile, Penny and Leonard must deal with a mistake from her past.

Leonard and Amy help Sheldon cope with the shame he's feeling after his accidental contribution to science is disproved. Meanwhile, Raj must stay with Howard and Bernadette for a week. IRA FLATOW...

While Sheldon is away in Texas, everyone gathers to decorate the apartment Christmas tree, and imagines what their lives would be like if they had never met Sheldon.

When Penny's big acting break on NCIS is a bust, Leonard struggles to help her, which results in Penny asking Leonard a bold relationship question. Meanwhile, Sheldon tries to learn how to be funn...

When Sheldon is forced to take a vacation, he tries to relax, but instead spends a lot of time with Penny after she quits her job. Meanwhile, Leonard struggles to be supportive of Penny and Bernad...

After they guys can't get Comic-Con tickets, Sheldon decides to hold his own convention, and winds up spending a wild night with JAMES EARL JONES (guest starring as himself). Meanwhile, the girls ...

Love is in the air when Amy convinces Sheldon to join her (as well as Howard and Bernadette) for a romantic weekend in Napa Valley to celebrate Valentine's Day. Meanwhile, Leonard and Penny must r...

When Leonard buys a dining room table, it causes Sheldon to reevaluate the changes in his life. Meanwhile, Wolowitz is offered a chance to go back to space and Bernadette struggles with whether or ...

Howard invites Sheldon to travel to Houston with him in an attempt to improve their friendship, while Penny's offered an embarrassing role and Raj asks Amy for help with a girl.

When Sheldon visits his mom (recurring guest star LAURIE METCALF) in Houston, he is forced to confront a new reality. Meanwhile, Raj's "Murder Mystery" party starts some fights within the gang.

While Raj is wracked with guilt over dating two women at the same time and Penny is wrestling with whether to take a role in a cheesy movie, Amy must help Sheldon through the even greater hell of c...

Sheldon faces a personal crisis after deciding he's wasting his time with String Theory. Meanwhile, a double date between Raj, Emily and the Wolowitzes ends in embarrassment for Howard.

Leonard tries to help Sheldon free his mind by reinstating "Anything Can Happen Thursday," but when Sheldon tries to be spontaneous, it leads to unexpected friction between Penny, Amy and Bernadett...

May the "Fourth" Be With You! Professor Proton helps Sheldon cope with grief, while Leonard turns a relationship milestone into a competition with Penny. Meanwhile Amy and Bernadette make a "Star W...

A horrible day at work prompts Penny to evaluate her life choices -- including taking a big step with Leonard. Meanwhile, Howard and Bernadette struggle to care for Mrs. Wolowitz, and Raj gets rela...

With his entire world changing around him, Sheldon is forced to confront an uncertain future and considers a major move in the seventh season finale. Meanwhile, Raj and Emily take it to the next le...

Highlights of the Q&A with the cast and creators

Cast members discuss the best romantic moments from Season 6.

Join The Big Bang Theory's executive producers and writers at the Comic Con 2013 Panel, discussing the creative process for the first time.

What happens when Kaley, Mayim, and Melissa encounter a precocious threesome who bear a striking resemblance to their younger selves? Cute overload!

Comedy folk duo Garfunkel and Oats (Kate Micucci and Riki Lindhome) lend their unique brand of songwriting to help Wolowitz serenade his quarantined bride Bernadette.

In honor of Star Wars Day, BBT enlists the help of legendary FX studio, Industrial Light and Magic to imbue Professor Proton (Bob Newhart) with the powers of a Jedi master.

When silver screen titan James Earl Jones makes a guest appearance on BBT, everyone knew it was going to be a blast, but no one suspected the man behind Darth Vader's voice would be laughing hardest!

Outtake footage of the Cast and Crew.

On the sixth season premiere, Howard discovers that he can't escape his mother -- even in space! Caught in an argument between Bernadette and his mom (recurring guest voice CAROL ANN SUSI), Howard ...

When Sheldon learns that Penny is thinking about breaking up with Leonard, he tries to intervene. But Sheldon is no good at keeping secrets. Meanwhile, Howard is being picked on in space by the oth...

While the pressures of being in space starts to take its toll on Howard, Amy feels threatened when Sheldon hires a young female assistant, Alex (guest star MARGO HARSHMAN).

When Howard returns from space, he doesn't get the hero's welcome he expected. Meanwhile, Game Night turns into a battle of the sexes.

The gang celebrates Halloween at Stuart's comic book store. Meanwhile Leonard and Penny discover a new spark in their relationship when he seduces her with science. And while Howard can't stop talk...

Sheldon's tenuous relationship with renowned scientist STEPHEN HAWKING is threatened by a game of "Words with Friends," while Penny secretly enrolls in a class at the local college.

Pressured by Bernadette, Howard comes to terms with moving out of his mother's house. Meanwhile, Sheldon, who's caught in the middle of a feud between his "girlfriend" Amy and good friend WIL WHEAT...

Howard and Raj try to get to the bottom of why Sheldon disappears every afternoon at 2:45. Meanwhile, Leonard and Penny wrestle with jealousy in their relationship.

When the University reassigns Sheldon's (unused) parking spot to Howard, the ensuing turf battle affects the whole gang.

Sheldon plays nursemaid to a sick Amy, while Howard attempts to bond with his father-in-law (guest star CASEY SANDER) on an upcoming fishing trip.

Sheldon unwillingly revisits some Christmas memories during a lively game of Dungeons and Dragons, while Penny, Bernadette and Amy try to find the perfect girl for Raj when he joins the girls for l...

Sheldon is accused of sexual harassment at the Univesity and winds up dragging Leonard, Raj and Howard into the fray. Southland's REGINA KING guest stars as the University's Director of Employee Re...

While the guys take a road trip to a comic book convention in Bakersfield dressed as characters from Star Trek: The Next Generation, Leonard's car is stolen. Meanwhile, the girls stay home and try ...

Outraged that he's being forced to work with his university nemesis, Barry Kripke (guest star JOHN ROSS BOWIE), Sheldon faces a crisis of conscience. Meanwhile, Howard and Raj spend a thousand doll...

A fight between Leonard and Sheldon drives Leonard to finally move in with Penny -- not realizing how the shift will affect Penny and Amy's living arrangements. Meanwhile, Raj takes care of Mrs. Wo...

While the guys try to give their significant others the perfect Valentine's Day, Raj and Stuart throw a lonely people party at the comic book store.

After a terrible date, Raj vows to never leave his apartment again. Meanwhile, Penny actually impresses Sheldon with her acting skills.

Back to school! Leonard, Sheldon and Howard try to advance the cause of women in science by speaking with junior high girls about their future careers, while Raj plans his date with Lucy (guest sta...

When Howard finds a letter from his father, he's forced to confront his past, struggling with whether or not he should open it. And Leonard and Penny throw a "grown-up" cocktail party at the apartm...

Let the battle begin! Leonard, Sheldon and Raj fight for tenure at the University -- and the competition heats up when the girls get involved!

Sheldon feels lost after one of his favorite TV shows gets canceled too soon, so Amy tries to help him get over his compulsive need for closure. Meanwhile, Raj discovers a secret about his new love...

Sheldon and Leonard hire Professor Proton (guest star BOB NEWHART), the host of their favorite childhood TV show, to perform. Also, Howard and Bernadette run into trouble babysitting Raj's dog.

When the girls' trip to Vegas falls through, the guys invite them to play Dungeons & Dragons -- causing Sheldon and Amy's relationship to take an unexpected turn. Meanwhile, Raj and Lucy go on a ve...

When Leonard is offered an exciting new job opportunity overseas, Sheldon grows very jealous and Penny is thrown for a loop. Meanwhile, Raj pushes Lucy a little too far in their relationship on the...

The fifth season premiere picks up where the fourth season finale left off as the gang deals with the aftermath of Penny and Raj's night together. While Penny worries that she's screwed things up p...

A battle of wills between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya (recurring guest star AARTI MANN), who has mov...

Leonard attends a co-worker's wedding as Amy's date. Meanwhile, Howard tries to convince Bernadette to live with his mom after they get married by suggesting a trial run with the two of them stayin...

When Raj is upset he's the only one of the four guys who is not in a relationship, Penny sets out to find the perfect date, introducing him to Emily (guest star KATIE LeCLERC -- Switched at Birth) ...

Sheldon's old nemesis, WIL WHEATON (guest starring as Himself), returns and invites everyone to a housewarming party. Sheldon threatens to "defriend" Leonard if he attends. But when he hears that B...

Craving a little motherly love, Sheldon competes with the gang for his mother's attention when she comes to visit. LAURIE METCALF reprises her role as Sheldon's mother, Mary.

A cute comic book artist (guest star COURTNEY FORD) puts Leonard's relationship with Priya to the test; while Sheldon, getting into the spirit of Halloween, tries to scare the guys.

Amy is heartbroken when Bernadette and Penny go shopping for wedding dresses without her.

Can friends with benefits still be friends without? Leonard and Penny try hanging out alone, while Sheldon must overcome his fear of birds.

Sheldon becomes jealous and considers taking his relationship with Amy to the next level when Stuart (guest star KEVIN SUSSMAN) from the comic book store asks her out on a date.

Leonard must face his fears after being contacted by his high school tormentor (guest star LANCE BARBER), while Penny realizes that she might have been a bully herself.

Sheldon gets in trouble with Amy when he isn't impressed by her recent accomplishment, and it's up to Penny to teach him how to be a better boyfriend. Howard, meanwhile, must come to grips with Ber...

The possibility of Leonard and Penny getting back together could prove disastrous when Leonard offers Penny a spur of the moment invitation to a romantic dinner for two on the 100th episode of the ...

Leonard and Penny experiment with dating again by "beta testing" their relationship, while Raj develops a peculiar relationship with his phone's virtual assistant.

Sheldon's selfish demands force Leonard to reconsider their friendship. Could this be the end of The Roommate Agreement? Meanwhile, Howard tries to pick his astronaut nickname, but NASA astronaut M...

When Sheldon is forced to take a vacation by the university, he goes to work with Amy in her neurobiology lab. Meanwhile, Bernadette wants Howard to sign a pre-nuptial agreement.

When a corner office at the University opens up, Sheldon must compete for it with his office nemesis, Barry Kripke. Meanwhile, a personal gift from Amy makes Penny uncomfortable.

Sheldon's life is turned upside-down after his barber becomes hospitalized. Now, that there's been a change in his routine, Sheldon finds himself re-evaluating his entire life. Meanwhile, astronaut...

It's on...like Alderaan, when the guys plan a weekend Star Wars gaming marathon! But when Sheldon chooses the guys-only weekend over a weekend with Amy to visit her aunt, he is destined to feel the...

It's a dream come true for Sheldon when he has a close encounter with his hero, Mr. Spock. Legendary sci-fi icon LEONARD NIMOY guest stars, lending his voice to a unique reprisal of his three-time ...

When Wolowitz gets tow work with world-renowned scientist STEPHEN HAWKING (guest starring as Himself), Sheldon is willing to do anything to meet his hero.

Howard's wedding plans are in jeopardy after the guys (and Wil Wheaton) throw him a bachelor party. After details of his sexual history are leaked online, Bernadette reconsiders marrying Howard.

When NASA reschedules Howard's mission and puts his wedding plans in jeopardy, he's forced to face his fears and Bernadette's dad (guest star CASEY SANDER). Meanwhile, Leonard says something surpri...

Howard Wolowitz crosses over into the final frontiers of space...and marriage on the fifth season finale. When Howard and Bernadette decide they want to be married before his NASA space launch, the...

On the fourth season premiere, Penny (series star KALEY CUOCO) finds herself along for the ride on Sheldon's (series star JIM PARSONS) first date ever. Meanwhile, Wolowitz (series star SIMON HELBER...

When Sheldon realizes he won't live long enough to download his consciousness into a robot body, he attempts to extend his lifespan. Apple Co-Founder STEVE WOZNIAK guest stars as Himself.

The guys are concerned as Sheldon searches for an alternative to human companionship after he and Amy (MAYIM BIALIK) break up. LAURIE METCALF reprises her role as Sheldon's mother.

An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work. Battlestar Galactica's KATEE SACKHOFF and Star Trek's GEORGE TAKEI guest star as themselves as W...

Leonard realizes he's the only one without a girlfriend, while Sheldon wants to get rid of his.

A visit from Raj's sister (guest star AARTI MANKAD) creates tension among the guys -- especially when Leonard keeps an affair secret from Sheldon, Howard and Raj.

When an FBI agent (guest star ELIZA DUSHKU) interviews the guys for Wolowitz's security clearance, Sheldon's answers during the screening, put Wolowitz's clearance in jeopardy.

When the guys camp in line for a screening, their plans are thwarted by Sheldon's greatest nemesis, WIL WHEATON (guest starring as himself). Meanwhile, Penny and Bernadette invite Amy to her first ...

Penny asks Leonard to lie to her father, Wyatt (guest star KEITH CARRADINE), while Howard, Raj and Bernadette pull an all-nighter at a telescope.

Amy finds she has sexual feelings for Penny's ex, Zack (guest star BRIAN THOMAS SMITH) while Koothrappali and Wolowitz try to prove who would be the better superhero.

The guys find a "super" use for Penny's new boyfriend, Zack, when they enter a costume contest as the Justice League.

Leonard's idea for a smartphone app derails his friendship with Sheldon as they fight for control of the project.

Tension runs high when everyone is staying at the same hotel for a science event and Bernadette runs into her ex-boyfriend (guest star RICK FOX, three-time NBA champion with the Los Angeles Lakers).

Sheldon wants Penny to give him acting lessons, hoping that they will help him become a better teacher. Meanwhile, Koothrappali fantasizes about his best friend's girlfriend.

A wealthy donor to the university makes Leonard consider how far he's willing to go for the sake of science. JESSICA WALTER (Arrested Development) guest stars as the widowed benefactress and JOSHUA...

As Wolowitz contemplates taking things with Bernadette to the next level, he must choose between his girlfriend and his mother. Meanwhile, Leonard rekindles his relationship with Raj's sister, Priya.

When the gang starts hanging out at Raj's and Sheldon realizes it's actually Leonard who is the center of their social group, Sheldon decides to get a new group of friends.

Leonard must choose between his new girlfriend, Priya, and his friendship with Penny. Meanwhile, Howard drives Sheldon crazy with a magic trick.

When someone hacks Sheldon's online gaming account, the guys go on a quest to find the culprit.

Sheldon and Amy experiment on their friends by spreading gossip, while Howard takes a big step in his relationship with Bernadette.

Priya uses her lawyer skills to pick apart the roommate agreement...and put Sheldon in his place. Meanwhile, the girls take Sheldon dancing.

Raj attempts to cure his social anxiety disorder of talking to women, while Penny uses Bernadette to spy on Leonard and his girlfriend.

When Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.

When Bernadette receives her Ph.D., the guys take joy in reminding an emasculated Wolowitz that he is the only one in their group who isn't a doctor. Meanwhile, Koothrappali becomes Sheldon's new r...

On the third season premiere, Sheldon (series star JIM PARSONS) flees back to Texas in disgrace when he learns that the guys tampered with his arctic expedition data -- forcing his friends to follo...

Leonard and Penny struggle to recover from an awkward first hookup, while Sheldon and Howard (series star SIMON HELBERG) stake their best comic books on a bet to determine the species of a cricket....

Howard and Raj (series star KUNAL NAYYAR) visit a Goth nightclub to pick up women, while Sheldon attempts to build a better Penny using chocolate-based behavior modification.

Raj must find a new job or be sent back to India. Sheldon, however, has a solution -- which leaves Leonard and Penny dealing with Howard as third wheel.

While Sheldon settles a score with his nemesis, Star Trek: The Next Generation's WIL WHEATON (guest starring as himself), Wolowitz begs Leonard to get Penny to set him up with one of her friends.

Sheldon teaches Leonard how to understand football, while a kite-fighting incident threatens Howard and Raj's friendship.

Sheldon plays the peacemaker when an argument between Leonard and Penny proves "inconvenient" to him.

With Leonard, Howard and Raj away camping in the desert, an injured Penny has only Sheldon to rely on.

After he's humiliated on National Public Radio, Sheldon vows to destroy Kripke (guest star JOHN ROSS BOWIE), and the guys help Sheldon exact his revenge. Meanwhile, Wolowitz tries not to destroy hi...

Sheldon takes on his greatest challenge when he attempts to help Penny understand physics, and Wolowitz becomes jealous when Leonard starts hanging out with his new girlfriend.

A visit from Leonard's mother (guest star CHRISTINE BARANSKI) delights Sheldon and horrifies Leonard.

While Sheldon and Koothrappali attend a university mixer, Leonard is upset to discover that Penny believes in psychics. DANICA McKELLAR (The Wonder Years) guest stars as the object of Raj's attract...

When their apartment is robbed, Leonard and Sheldon turn to their friends to create a state-of-the-art security system -- and Sheldon struggles to cope.

Suffering from a case of "physicist's block," Sheldon's search for the answer to a physics problem leads him to work at the Cheesecake Factory with Penny.

It's Valentine's Day, and Leonard can only bring one guest on a trip to see CERN's Large Hadron Collider (the world's largest and highest energy particle accelerator) in Switzerland. Will it be She...

Sheldon misses his chance to meet comic book legend STAN LEE (as himself) when he winds up in traffic court after he gets a ticket because of Penny.

When the guys find a rare movie prop ring from The Lord of the Rings at a garage sale, it threatens to tear them apart -- forcing them to choose the ring or their friendship.

Sheldon's friends come to his aid when his fear of public speaking stands between him and a coveted award.

A fight between Leonard and Penny threatens their relationship, while Sheldon battles WIL WHEATON (guest starring as Himself) in bowling.