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.
Fixes to mlctf1beta a.k.a. "Encephalomalacia", made originally by [uM]Meisterlampe for Q3A, released under GPLv2 in 2011, and included in OA 0.8.8. This version returns to the original map (removing, among other things, the invisible walls in the bases) and adds special FX.