OpenArena is a community-produced deathmatch FPS based on GPL idTech3 technology. There are many game types supported including Free For All, Capture The Flag, Domination, Overload, Harvester, and more. There are 17 unique player models to choose from and 12 weapons.
Uninteresting gameplay, markets itself as a "shooter for adults" and therefore tries to make it's sad attempt at becoming a better game by giving female characters as little areas covered by clothing sound less sad.
This game is a waste of your time.