well heres the homepage [*cough*].
its a completely free to download multiplayer based first person shooter for Mac, Linux and Windows. i heard rumors about urban terror being like "the old quake". well what more to say? try it out, it might take a while but i think thats worth it. my ingame name is Shockwave@MacOsX if someone plays it. you can easily search people in the server list by clicking on "Find Friend". btw: that would be a nice feature for toribash too ;]