It can be interesting to sample for those of us that love anything Quake based, for starters.

From my understanding these 'games' do not require standalone Q1 or Q2 to be installed.
Here is the list:
CodeRED: Alien Arena - [Based on Q2] -- http://www.planetquake.com/cor/arena/ -- [Released]
Argonium - [Based on Q2] -- http://www.planetquake.com/td/argonium/ -- [Released]
Nosferatu - [Based on Qfusion/Q1] -- http://www.nosferatuthegame.com/ -- [In development]
Nexuiz - [Based on Darkplaces/Q1] -- http://www.nexuiz.com/ -- [Released]
OpenQuartz - [Based on Darkplaces/Q1] -- http://openquartz.sf.net/ -- [Released]
Digital Paint: Paintball 2.0 - [Based Q2] -- http://dynamic.gamespy.com/~digitalpaint/news.php -- [Released]
Warsow - [Based Qfusion/Q2] -- http://www.warsow.net/ -- [Released]
Ok, so they might not feel like 'full' games to some... but that dosen't mean it can't be fun!
