For quake3, hit the ~ key at the menu, then type timedemo, hit enter, and then demo 001. Let the demo run and then hit the ~ key to see what you're at.
For UT, you can go to tools/timedemo statistics and it will show your average framerate so far in the level, and your max framerate. At the end of the level/match/whatever, it will give a short summary.
You may also want to get 3DMark 2001. You can get it from <A HREF="http://www.madonion.com" target="_new">http://www.madonion.com</A>.
Lyrics. Wasted time between solos.