I haven't done a write-up yet, but my partner and I use MIDI as part of our custom lighting setup, which we bring to gigs and other events. A MIDI controller is hooked up to a raspberry pi running some Python software. We use the `mido` library for decoding MIDI. We then drive a bunch of RGB LED strips using DMX. Video: https://www.instagram.com/p/BtjLSUeFjtJ/.