Boards
Audiosurf
seen this? It's a puzzle / rhythm game a bit like guitar hero, but you load your own MP3 into it, which it turns into a 'track' to fly along and you have to collect cloured squares and stuff that are the drumbeats and it's AMAZING.
I wouldn't recommend Dillinger Escape Plan for your first try though...
The demo only lets you do 4 tracks (you can get it from Fileshack etc if you don't fancy installing Steam) but it's dirt-cheap if you want to buy it (or free if you know where to look...)