It's important that you have the game's two CDs available.

1. Download the Linux installer from here: http://www.liflg.org/?catid=6&gameid=51 (the file named unreal.tournament_436-multilanguage.goty.run)
2. Open Terminal and go to the folder where you downloaded the file.
3. Write "sh unreal.tournament_436-multilanguage.goty.run" in Terminal.
4. Install the program with the selections you want. When you have put the CD 2 in, the installer gets stuck for a long time, but don't worry: the computer just extracts the game's map files. You can monitor the process in Terminal.
5. When the installation is complete, go to the location where you installed the game (default /home/(user)/ut) and open the System folder inside it.
6. Locate the file ut-bin and double click it. The game starts in a minute or two and you should be able to play it.
7. As default the command "ut", which is used to launch the game, doesn't work in Terminal, but it can be set to work by running a command "sudo dpkg-reconfigure dash" and by answering "No" to the query that comes in front of you. If Terminal says: "Couldn't run Unreal Tournament (ut-bin). Is UT_DATA_PATH set?", you must give it the command "export UT_DATA_PATH=/usr/local/games/unreal/System" (if your path is different, replace that with it).