Below is a link to a music game I created in the Blender game engine. It's fairly intuitive, although there is no fixed objective. You are the green cube, you move around with W S A and D; press space to change level (and Q to fly in level 3) and crash into the other geometric shapes. When you do so, music will start playing. A different loop will play for each different shape you come into contact with. You can try and hit them so the loops play in time with one another, which is challenging, or in the ambient level, hit them whenever you choose.
There is no way to stop the music playing once it has been started but you can, with some effort, push the shapes off the edge. They will take the music loop with them and you'll even hear the doppler effect as they pick up speed and fall into the void. Be warned though, you can also fall off!
Download .zip (From Mediafire)
Unpack files and open game.blend to play. If you don't have or are not familiar with Blender, click in the 3D view window and press P to play after downloading, installing and opening game.blend :)
More info and (free) download of Blender can be found here: www.blender.org
