Hypercam 2 doesn't involve paying money/pirating either, only Hypercam 3 lol.
And about the audio, I'll wait to see what Jethawk says, but I think it would be cool if everyone recorded just sound effects and then, instead of having the music switch suddenly between different songs (which would sound awkward) have somebody do a sort of medley type thing which connects the movie clips naturally with music from each mod. I'd be willing to do that, but if anyone else (you or Jethawk or anyone who's interested) would rather volunteer, I'd be more than happy to relinquish that job since I'm already rather busy. Or it might be that Jethawk has some other plan for the audio in which case ignore this.
Also, how does one make CS only play sound effects and not music? A really simple assembly hack, I'm guessing?