The music is made by 2 identical tesla coils. If you don't recognize the music this is from the Mario Brothers game (a very popular old game)
The Tesla coils stand 7 feet tall and are each capable of putting out over 12 foot of spark. They are spaced about 18 feet apart. The coils are controlled over a fiber optic link by a single laptop computer. Each coil is assigned to a midi channel which it responds to by playing notes that are programed into the computer software. These coils were constructed by Steve Ward and Jeff Larson. Video was captured by Terry Blake.