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.
This game is average at best. While it prides itself on being a strictly free and open source first person shooter, other free and open source shooters - such as Xonotic and Red Eclipse - blast OpenArena out of the water.