Last week Crystal and I reworked the chorus of our Perimeter and Area Song. (It's part of our ongoing elementary project for math music videos.). I really like what she did to put life into the melody and I easily adjusted the chords into something I was pleased with in UJam.com. I experimented more with adding different instrumentation, but I still had the basics of the song elements done in about 20 minutes after downloading her new vocal track.
The video could be a lot better, but right now I'm seeing what I can do with just iMovie on the iPad. And as far as that goes, all mixing was done in GarageBand on the iPad. I think I'll do an iPad version, then one that uses more options from robust editing software on computers.