NOTE: The process for setting up the dev environment has changed. Please refer to the docs for details. It's both a startup and a community project, completely open source under the MIT and Creative Commons licenses. It's the largest open source CoffeeScript project by lines of code, and since it's a game (with really cool tech), it's really fun to hack on. Join us in teaching the world to code! Your contribution will go on to show millions of players how cool programming can be.