Although I’ve no time right now to play it, Audiosurf mentioned on GameSetWatch looks dead fun, and is especially apt for one of the roundtable entries suggesting user-created soundtracks, since it takes any input MP3 to play – see Mr. Blue Sky being played!

I’ll have a go later, and I’d suggest others try it too – I’d better check out the other IGF entries if since this certainly looks like a worthy finalist!