The strange, seemingly cacophonous stream of sounds coming out your speakers is GlitchDS, a homebrew cellular automaton music sequencer inspired by Conway's Game of Life. Developer Clone45 boasts that the program (his first) is "perfect for creating IDM and Glitch-style loops," and, while we have no idea what that means, we're sure he's representing the software accurately with that claim.
In addition to being free and odd enough to be awesome, GlitchDS allows you to create "trigger points," import your own audio files, save/load your work, control tempo with BPM settings, edit sounds with a 32-step frequency modulation sequencer, load six sounds at once, and fiddle with global distortion settings. If you manage to make any music with it, make sure to send it our way!
See also: Homebrew Week, Friday Video: Two DS Lites and a microphone