cards-against-gmod
Cards against GMod is a chat-based version of Cards Against Humanity for GMOD. This allows players to play CaH (or, rather, CaG) while in-game. No docs yet, but the majority of the code is in sv_cag1.lua and is a pretty easy read. You can also say "!cag help" in game for in-game docs.
The questions and answers are, of course, directly from CaH (and covered under their Creative Commons license). Anyone who isn't familiar with CaH, be warned -- they can get quite vulgar. Sense of humor needed. :)