Years ago, I did a museum installation for some wacky artist, one component of it was interactive; Push the button, and from a slot in the ceiling, 20 feet above, a garage door opener would pay out a tape reel, on the end of which was a white tuxedo gloved hand. It would drop down and strike a single note on a piano keyboard, then retreat and reset. Thought I would go nuts just trying to get something that simple to work reliably.