http://www.fraps.com/I don't really like fraps, but it is what I use. What I do, is use the normal demo recording, and while playing that back, use fraps to capture the video clips that you want from the demo.
Why I don't like it so much:
With the free fraps, you can only record for 30 seconds at a time.
I can never seem to get the recordings from fraps to look as smooth as when I play tribes. It looks all laggy and what not.
