"Two music games got it right on the DS this year, both eschewing fancy controllers, instead focusing on the system’s touchscreen to present their engaging concepts: Rhythm Heaven and Maestro: Jump in Music." Ooh, sounds interesting - will have to hunt that down. (Via Simon Parkin)

"VideoGamesHero brings you homebrew action at it's best - offering lasting fun and challenging action with over 65 Songs, 5 Game modes, Motion Card and Guitar Grip support, there is something for everyone!" Homebrew Harmonix-style rhythm action game for the ds. Awesome.

"the nintendo ds is an excellent platform for homebrew audio software - here’s an (incomplete) list of some of the excellent sound toys that are available for the platform." Awesome. More listed in the comments, too.

" Protein[DS] is a little audio manipulation software running on Nintendo DS, which ables you to manipulate audio, anywhere you go - it is in some ways similar to ElectroPlankton concept."

"glitchDS is a FREE homebrew Cellular Automaton music sequencer for the Nintendo DS. It’s perfect for creating IDM and Glitch style loops." Should only work with R4, but seems to work with several carts.