There is a mod called Quest: The Lost Realm, an rpg for hl1. The mod has been in developement for years now, and is coming along nicely, but their coder has left. They desperately need someone to code for them! The rpg is 3rd person and everything, go here for details.
http://quest.planethalflife.gamespy.com/
Post in the forums saying you are willing to code for it and they will most likely put you on the team. Don't let this mod die now just because thier coder left! Save them!