It's not related in any way to AGS, but it has an adventure game quality to it.
Puzzlemania - A Community Effort (http://forum.facepunchstudios.com/showthread.php?t=57000)
I'm just bringing this up for anyone that's interested in volunteering. The idea is to first solve the puzzles in the newest version of this map, PM the latest author with the codes, and then you'll be put in line to add your own puzzle to the project and post it online. It requires registration to PM someone and the Source Engine Tools to work on the map, but you're free to just play the current map if you'd like (It's also got a part in it made by me ;D).
I'm just bringing this up because we're low on volunteers (like 5) and I don't want the thread to die.