This is a "drum machine" I put together in Unity for a course earlier this year. The apples represent a single note and whenever they collide with a solid object, they play the note over MIDI. You can place spawners for more apples, place platforms for more complex motion, and portals to allow for chaotic teleportation. Good luck putting together a 4/4 groove!
I don't currently have access to a VR headset to test on, but if you can get it running please send me a video!