Strange musical machines
Who knew you could play the theme song from Super Mario Brothers with a Tesla coil?
So just to explain a little further, yes, it is the actual high voltage sparks that are making the noise. Every cycle of the music is a burst of sparks at 41 KHz, triggered by digital circuitry at the end of a "long" piece of fiber optics. What's not immediately obvious in this video is how loud this is. Many people were covering their ears, dogs were barking. In the sections where the crowd is cheering and the coils is starting and stopping, you can hear the the crowd is drowned out by the coil when it's firing.
More about Tesla coils at Wikipedia. (thx, mike)
And I don't know what rock I've been hiding under for the past 33 years, but this Gnarls Barkley cover is the first I've heard of the theremin music machine:
In a great illustration of the sometimes odd path that innovation takes, Robert Moog found inspiration in the theremin after it had fallen out of favor in serious musical circles:
After a flurry of interest in America following the end of the Second World War, the theremin soon fell into disuse with serious musicians, mainly because newer electronic instruments were introduced that were easier to play. However, a niche interest in the theremin persisted, mostly among electronics enthusiasts and kit-building hobbyists. One of these electronics enthusiasts, Robert Moog, began building theremins in the 1950s, while he was a high-school student. Moog subsequently published a number of articles about building theremins, and sold theremin kits which were intended to be assembled by the customer. Moog credited what he learned from the experience as leading directly to his groundbreaking synthesizer, the Minimoog.
Update: Theremin: An Electronic Odyssey is a 1994 documentary about the theremin and its inventor. Here's a trailer, a review by Roger Ebert, and the DVD from Amazon. (thx, jeb & mark)