"rpm -Uvh quake2-3.20-glibc-6.i386.rpm"
Or "tar -zxvf quake2-3.20-glibc-i386-unknown-linux2.0.tar.gz"
"cp q2.script /usr/lib/q2" Or another directory in your path
"cp pak0.pak in /usr/local/games/quake2/baseq2/"
"chmod g+x /usr/bin/q2" Make it executable by the group
"chown root:(your userid) /usr/bin/q2" Make you ID the group ID
In a x-terminal do: "q2"
Read the q2 script for instructions on how to change resolutions
Enhancements: (like more resolutions than 640x480)
To get resolution higher than 640x480, you will have to recompile Mesa with these changes. I also have a howto for Mesa development linked from the previous page.