Jin-Yo Mok's and Gicheol Lee's Music Box, an interactive music installation that uses LEDs instead of the regular music box pins, lets users draw an image on a monitor, which will then be re-created on the music box when the crank is turned. All the data is saved so previous users' pictures can be played again. There are videos available on the site, and watching the box play/light "Twinkle Twinkle Little Star" is mesmerizing. The online version (click on "Play_Online") isn't quite the same visually, obviously but I can't stop playing with it. It seems impossible to play something that doesn't sound whimsical and pretty. If you create a masterpiece, be sure to save it so that others can enjoy it too.
Music Box is featured in the Whitney Artport.