OpenArena is an open-source content package for Quake III Arena
licensed under the GPL, effectively creating a free stand-alone game.
You do not need Quake III Arena to play this game.
OpenArena has bots, network playability, many maps and most of the
other features you would expect from a commercial first person shooter.
OpenArena requires 3D accelerated video drivers but runs quite well on
the open-source Intel drivers.
Please be advised that the main game zip file, openarena-0.8.8.zip, is
about 405MB. This file is already patched with the 0.8.8 patch. Also,
the download site listed in the openarena.info file is a direct link,
but it is sometimes slow. You may wish to visit the openarena homepage
(openarena.ws), click on "Downloads," and look for much faster download
sites that do not offer direct links. Just make sure you find the full
zip that includes the 0.8.8 patch.