SRC Repair (ex. TF2 Repair) is a free open source tool that can be used for tuning and cleaning up Steam and Source engine games. You can also create and edit .cfg files (configs), backup and restore game settings, apply FPS configs or sprays into the game with one click.
Pretty cool! What language do you use? I'm interested in what you use. An another note, if you don't mind, I'd like to work with you in creating a HUD maker. I've got quite a lot of experience with programming and HUD making itself, so I think this program will be quite interesting to create!