Alien Arena 2007
Alien Arena is a completely free FPS started by COR Entertainment in 2004 comprising of a science fiction ambience and a Quake like gameplay. This game is playable in single player mode against bots, but the action and thrill lies at the online multiplayer mode. Features of the Alien Arena 2007 include an internal server browser for finding other people to play online and an external program that acts as an IRC interface.
There are 6 game types and 6 game mutators that changes the gameplay. Cattle Prod is a new game type that requires you to herd robotic cattle to earn points.
Alien Arena 2007 is playable in Windows, Linux and FreeBSD.