the downloadable UT2003 demo for linux is a demo, not a full version, it has one or two maps for each type of game mode it has, and it is an online demo too. The full UT-client is not free, you must buy it. And the linux installer for it is on CD3 of the 3 cd set, i didn't see anywhere on the box or manual where it says u can install it on linux, but sure enough it's there. I've been playing it for 2 weeks now, it's awsome