Touch based audio livecoding in assembler, for the Nintendo DS. Source code and rom. Based on the original Betablocker. If you don't have a DS or passcard for running homebrew, you can use an emulator. I've been using no$gba under wine on Linux for testing.
Homebrew is the name given to software used on a device which has been compromised to subvert controls put in place by the company that manufactured it. Homebrew is considered fair use by law and legitimises the reverse engineering required to support such activity.