These ebuilds come from http://gentoo.zugaina.org/.
If you have some problems, go to the official site first.
cube : Landscape-style engine that pretends to be an indoor first person shooter engine ( http://wouter.fov120.com/cube/ )
edm : a fork of the Sauerbraten FPS engine which adds new gameplay and engine features. ( http://edm-fps.net/ )
nexuiz : Deathmatch FPS based on DarkPlaces, an advanced Quake 1 engine ( http://www.nexuiz.com )
openquartz : Open Source PAK Files for Quake based games ( http://openquartz.sourceforge.net/ )
quake3-openarena : Open-source replacement content for Quake 3 Arena, effectively creating a free stand-alone game ( http://cheapy.deathmask.net )
tremulous : Team-based aliens vs humans FPS with buildable structures ( http://tremulous.net/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a zugaina
For Paludis use this rsync : rsync://gentoo.zugaina.org/zugaina-portage
If you have a problem : ycarus(-at-)zugaina.org