The SL Viewer is an openly developed SIM game; where residents explore, purchase virtual land, open businesses, build real estate, and create scripted objects such as cars, robots, or magic wands.
Nexuiz is an open source multi-player first person shooter game, based on the Quake v1 - Darkplaces engine; presently available for Linux, and Windows users.
VDrift is an openly developed, SDL-based car racing video game based on the popular Tokyo Drift; for Linux and Windows systems only, and with LAN capabilities.