This fascinating gizmo, called the Super Mario Spacetime Organ by Chris Novello, lets the user create fascinating musical remixes using Nintendo sound effects and game sound.
Since any level in an old NES game such as Super Mario Bros is held entirely in the system's RAM, the organ can play back segments of gameplay and manipulate the game sound to create unique creations. Obviously, Super Mario wasn't quite intended to be played this way, so it causes some really neat visual glitches while making compelling game sound at the same time.
Novello states, "the Soundplane is multitouch, so I use a second finger to specify start and endpoints in a playback loop. Technically, this is similar to the way samplers and granular synths work in audio, but with the entire memory state of the NES. Conceptually, it is like Super Mario meets Groundhog Day. Mario’s universe computer/time machine gets caught in hellish loops."