Here is a project where a USB playstation controller is used to alter playback information for a set of sampled sounds. Its also connected to a playstation emulator (called PCSX-reloaded) and so by simply playing the game you are creating the music.

I arranged and recorded a rock version of “Scotland the Brave” for the flash game “Rock with The Blow Hards” as part of Susan Carpenter’s online story The Year of the Rabbit Comes to Scotland

Rock with the Blowhards - Play game