From LQWiki

Quake 3 Arena is the third game in the Quake series from ID software[1].

A First Person shooter, focus of the game lies at online multiplayer deathmatches.

Quake 3 Arena can be played natively on Linux. Many mods also work, including the Urban Terror mod. The Team Arena expansion is also available for linux.

Installing

Download the latest Quake 3 Arena point release (here). Install. Copy the pak0.pk3 file from the baseq3/ directory of your cd (or harddisk) to the newly created baseq3/ directory on your GNU/Linux system.

Acquiring

You can still buy the special linux version of the game cd, which comes with an installer on the CD. One place to buy it is http://www.tuxgames.com/