Putting the Pi in Piano
This piano piece by Tom Dukich was created by assigning notes to the digits 0 through 9 in the constant known as pi. He plays the scales forwards and back at the top, then the 3, and I'm assuming that honk is the decimal point. Hypnotic.
He has also done another version of pi performed with piano, bass, and flute that is either more interesting or not, depending on your taste.