Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux. Xonotic is a direct successor of the Nexuiz Project. The project is geared towards providing addictive arena shooter gameplay which is all spawned and driven by the community itself. Xonotic is a direct successor of the Nexuiz project with years of development between them, and it aims to become the best possible open-source FPS (first-person-shooter) of its kind. New trailer coming soon Please post all support issues in the forums for the game.

n3wu53r says

10/10 - Agree (8) Disagree (1)

Amazing free game.
Better then Nexuiz (which this game is based on).
Not a lot of players on servers but fi you on their forums there is a thread about pickup matches that happen on IRC.