This app displays the brilliant xkcd comic "Now" as a widget on your homescreen or on your lock screen.
It shows current business hours around the world so you know when to contact your partners, friends or clients.
The widget rotates in sync with the Earth (assuming the Earth continues spinning).
+ the smallest "Now" widget: less than 1 MB instead of 25MB
+ lock screen compatible
+ No permissions needed
+ ad-free and gratis
Source of the comic: https://xkcd.com/now
Detailed explanation: http://explainxkcd.com/1335/