BetaBlocker is a livecoding performance and a piece of software. It's a virtual acid techno machine which is live coded with a gamepad or touchscreen to create code and processes which modify and destroy each other in 256 bytes of memory. The machine's memory and processes are projected and integral to the performance.
Beginning as a performance prototype in Fluxus, Betablocker then moved to Gameboy DS as homebrew software. 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. Download the rom here and find the source here.
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.