In a nutshell, you get a group of people together, select a category, and then hold your word up to your forehead. From there, you've got 60 seconds where a word will appear on the screen, everyone else shouts clues, and you try to guess it. If you get it right, you tilt your device down, if you can't get it and want to skip you tilt up. It sounds basic, but even beta versions of the game that randomly would appear at bars and restaurants of GDC was a ton of fun.