What do you use to record in Linux?

[MisterFister]

Ladies and germs, I've decided that 3.6GB of ram is not enough to satisfy me. So, I've gone through the trouble to reformat and partition my hard drive so as to allow a dual boot configuration with Linux, since the 64-bit version of KSP is quite stable in Linux.

However, Fraps, the vidcap software I've tinkered with in Windows, doesn't work outside of Windows. So, to Linux-based YouTubers out there, what do you use for vidcap software? (Preferably software that generates .avi output files, though exact codec / format is negotiable. IDEAL is something free or low cost, though I'll consider paying, especially if a trial version works out on a few test runs. Better yet is something that can record multiple independent audio streams, so I can divorce live voiceover audio from in-game audio.

Any thoughts or suggestions? I've googled the question and being peculiarly new to Linux, and my YouTube experience so far as been as a contributor to others' channels [meaning the actual recording has always been done either in Windows, or on someone else's machine entirely] I'm not exactly sure what I'm looking at.