BEATNVISION did a tutorial on how you can use the chibi:bit as a Bluetooth MIDI controller for iOS! This looks like a seriously fun way to play. Now we just need to figure out how to get one. Amazon Japan has lots of fun stuff! I couldn't find an American or European distributor for the chibi:bit, but I did find this thing.
How to connect chibibit to iOS
chibi:bit (BBC microbit compatible) plays GarageBand for iOS via MIDI over Bluetooth Low Energy (Bluetooth MIDI)