The graphics quality has been reduced to make it smaller. I replaced the ioquake3 engine with an ioquake3 engine I compiled several months ago. The engine included with Open Arena requires openAL. This one does not. It's a 18MB download:About OpenArena
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.
Bots were added starting in 0.6.0. They will spout taunts and everything!
http://dotpups.de/dotpups/Games/OpenArena-tiny.tar.bz2
Thanks to MU for hosting!
You'll need SDL and Hardware video accelaration.
If you like you can download the High quality version. I think it's 84MB.
The Open Arena home page:
http://openarena.ws/
There are many mods for quake3, to install a mod just place the mod's folder in the same directory as the base3q folder. Then start the game and select mods from the menu.
Some good mods:
Urban terror (448MB) http://www.urbanterror.net/news.php
Reaction Quake (493MB) http://www.rq3.com/
Western Quake (163MB) http://forums.westernquake3.net/