Two music boxes based on space, one using the galaxy spinning round Polaris and another using our solar system spinning round the sun (minus the Kuiper and asteroid belts, someone should make one just of those). Try playing them at the same time!
PS. On the subject of randomness in music I like the first 15 seconds of this video where a man transcribed the position of birds to music:
PPS. I was going to post Aphex Twin's video for Nannou but found this instead:
I just ordered my own modifiable music box here.
PPPS. Here's the original schematic for E.T.'s communicator: