This is only one person! I got a haircut, it's not like my brother or anything :P
This is my a cappella version of Stickerbush Symphony (composed by David Wise) from the Bramble Blast level of Donkey Kong Country 2, and I made it into a medley with the remake (Arrangement Supervisor: Michiko Naruke) that was created for Super Smash Bros. Brawl. This is one of the best video game songs out there... I've seen a site rank it as the #1 "western" video game song (which I think basically means not composed by a Japanese guy).
I arranged this for voices purely for the purpose of recording it myself. I recorded the audio using a basic condenser microphone connected through an MBox 2 mini to my computer. I used Pro Tools LE to put together all of the audio. A quick note to say that I'm not a fan of making general vocal stuff perfect, so if something was imperfect but didn't bother my ears too much, I let it be.
The video was recorded using a basic external webcam, and then everything was put together using a wonderful program called Screen Flow.