While the ioquake3-powered OpenArena game is not as advanced or popular as say Nexuiz
, it is a fairly popular free software game amongst those using an open-source Mesa3D driver stack. It's not too graphically rich yet provides competitive and fun FPS game-play -- it can also be used for Mesa driver benchmarking.
The last notable release of OpenArena was OpenArena 0.8.1 and it came way back near the end of 2008. Since then there hasn't been anything in the way of major developments to report on, but today they have jumped to OpenArena 0.8.5 and have released it as a patch.
OpenArena 0.8.5 offers new effects (rocket smoke, shotgun sparks, flares), new maps, improvements to existing maps, improved CTF skins, and new skins for other in-game characters.
Details on the OpenArena 0.8.5 patch along with Linux download links can be found in the OpenArena Forums