I've known about CamStudio for a while (and likely all of you have too), but I never bothered with it because my old computer was too weak. Now that I have my new one, I thought I'd try it out. I think it's absolutely fantastic.
Of course I got down to serious business right away: Making a quick demo video of a PC game to show to some friends who'd never heard of it:
All of that video is only about 3 MB. I imported a huge .avi into Flash and compressed it. Importing the video clips is pretty easy, so I may use CamStudio more in the future. Go get it, if you can; it's a great free way to demo.