This wiki is a work-in-progress containing some useful lists and how-tos on advanced CoffeeScript topics. It does not contain authoritative documentation on the language. If you're just getting started with CoffeeScript, the best free resource is the official site. There are also several books: The Little Book on CoffeeScript, Smooth CoffeeScript, CoffeeScript: Accelerated JavaScript Development, CoffeeScript Ristretto, and Programming in CoffeeScript, and cheat sheets at Cheatography.
For general discussions and questions about CoffeeScript, see the Google Group