You've probably heard the ethereal theremin, often called the first electronic instrument, in countless scifi movies and the Beach Boys song "Good Vibrations." A simple device which produces sound when your hands come into contact with an electro-magnetic field, it was invented by an engineer named Leon Theremin in the early 1920s. An amazing documentary from the early 1990s called Theremin explores the life of this bizarre inventor, who also created the first perimeter alarms, passive listening devices, and color television. You can see him performing here in the early 1930s. He stunned the New York art world with his interracial marriage to the American Negro Ballet's prima ballerina Lavinia Williams, and then disappeared mysteriously in the late 1930s.

Leon Theremin: Rocker, Lover, KGB AgentTurns out he'd been a KGB agent all along, and had to return home to get back to work on his surveillance devices. He was imprisoned for many years, and forced to work on listening devices, when it seemed that all he really wanted was to build weird musical instruments. While in the U.S., he had set up an electronic music lab and hung out with Einstein and dozens of famous modern composers. He also romanced the young Clara Rockmore (who later became a theremin virtuoso) in the geekiest way possible. He designed a device (pictured) that moved when her body came close it it, then put her birthday cake on top. So when she approached the cake he'd gotten her, it slowly spun around. This documentary is completely fascinating, and also incredibly depressing. Theremin really just wanted to be a music geek, and his life was torn apart by Soviet politics. Still, he reported later that one of his proudest moments was teaching Lenin to play the theremin (apparently Lenin was pretty good at it). You can read an interview with Theremin that gives a lot of backstory on his life here, though it's sad that he's forgotten almost everything — and had some of his own life brainwashed out. Or you can watch the documentary. [Theremin via Amazon]