Word of the Day: Theremin
You can hear the theremin in the soundtracks of such productions as The Day the Earth Stood Still, The Lost Weekend, or My Favorite Martian. (That was the theremin you heard every time Uncle Martin levitated.) The Rolling Stones used it, Simon and Garfunkel used it, Led Zeppelin used it. Also a couple of my very favorite bands: The Pixies and The Mars Volta.
The theremin has two antennae. One controls pitch and the other, volume. Waving your hands around the antennae creates the sound. In theory it's easy; in practice, extremely difficult. Hand movements must be very exact, while the rest of the body remains absolutely still.
The theremin is the nerd instrument par excellence, more fun to build than a ham radio. In the 1950s, Robert Moog built one while he was a student at the Bronx High School of Science. The rest is history.