Back in the day, if your NES or SNES games started to get glitchy, there was one go-to solution: remove the cart from the console and blow into it as hard as you could to clear the dust from the circuits. This would allow you to resume play.
This is the concept behind 8bit Harmonica (which is more like a set of panpipes than a harmonica), a musical instrument created by Basami Sentaku (Japanese for clothespin). Housed in an old Famicom cartridge, it consists of a set of "pipes." These are programmed to reproduce chiptune sounds as heard in the original Super Mario Bros. When you blow into them, you can play music instead of games.
Since the notes can only be played one at a time, you need a small ensemble to play multitrack tunes -- and speeds are, as evidenced in Basami Sentaku's video below, a little on the slow side -- but it's still a pretty clever (and deeply nostalgic) idea. We'd love to hear some original tunes composed on the instruments.