During High School I decided the best way to learn to program would be to make a mod for the oldest open source game I could find, Wolfenstein 3D.
Unsung is a WWI themed total conversion featuring all new levels, extensive changes to the games code, new art, sounds, and music. The art of Jacques Tardi had a big influence on the mod's theme and art style.
Afterwords I worked on porting it over to run on the SEGA Dreamcast.
Download links can be found at: