Group leader (teachers, coaches, club presidents): Automate class attendance by having your participants "check in" with their phones.
You: Make an account at https://youhere.org, and create a class. Set your attendance requirements, such as your classes (GPS) location and meeting times.
Your participants: Uses this app to 'check in' to your event.
The app uses the phone's location capabilities to see if they're in the right place at the right time (according to your attendance requirements). Results are logged to your Youhere.org account.