This page provides a guide to installing and configuring Nexuiz, a multiplayer first person shooter freely released under the GPL.
Before starting the game you may need to disable Desktop Effects, or you could get display errors or the game could run too slowly (this may be not needed on an nVidia card with proprietary drivers).
Nexuiz is a graphically demanding game which requires Direct Rendering.
If following command returns "No", see Video to install the proper drivers for your video card.
glxinfo | grep direct
Nexuiz - The Nexuiz homepage with support forum, FAQ and more info.