Has anyone tried Sauerbraten or Starsiege:2845 yet? They both sound kinda cool.
I play Sauerbraten a lot and randomly make and modify maps in co-op with friends on it. It's great game and the Cube 2 engine is really sweet, but online play is mostly DM and can get boring, luckily many other projects are using the Cube 1 and Cube 2 engines to make RPGs and other FPS gametypes.
There is even a commercial game in the works by some indie-software company that has been looking very promising.
Right now I just play Sauerbraten for DM and
ActionCube for TDM.