[tlug] Anyone play games, like Doom 3, on Linux?

[Dave M G <martin@example.com>]

TLUG,

I downloaded the demo version of Doom 3 for Linux the other day, and it 
worked amazingly well. Smooth rendering, fast load times... much better 
than I thought a game would be on Linux.
So I thought, hey, this is cool, I'd like to play the whole thing.

I hoped maybe I could buy and download online, but it seems that what 
one needs to do is buy the Windows retail version, then copy some files 
from the CDs and apply a Linux patch to get it to work.
It sounds a little dodgy. Has anyone done this? Any problems? Was it 
automagic?
And, further, does anyone know of a place to buy slightly older games 
like Doom 3? I think it came out in 2004, which in the gaming world 
means it's ancient history.
There was a guy selling a copy (along with other games) on the Tokyo PC 
User's Group, but he never replied to my inquiries.
I probably shouldn't invest too much time into making a game run on my 
system, as it will just eat time. And my printer still doesn't work... 
but all work and no play makes... um... something. I don't remember the 
rest of the quote. In any case, a few pointers on installing, playing, 
and acquiring games for Linux would be appreciated.
Thanks for all your time and help.

--
Dave M G
Ubuntu 6.06 LTS
Kernel 2.6.17.7
Pentium D Dual Core Processor
PHP 5, MySQL 5, Apache 2