I've seen YT videos and blog posts here of contests screencasts (mainly from dj3500), and I was planning to do a screencast. But the thing is I don't know what software to use. I was wondering what lightweight video capture program I can use, because the only one I know of is Camtasia Studio, and that's anything but lightweight. On the contrary, it's so CPU-heavy that I believe if I were to capture 2 hours of HD video nonstop, my hard drive would blow into a thousand pieces and my CPU would heat up to the point it would melt the motherboard, the case and the table that supports it.

Anyway, I'd appreciate if someone could englihten me on the matter and share a lightweight video capture program I can use to record a screencast.

Thanks in advance!