About 22 years ago, I was doing a day-release Engineering course at a college where they had a CNC machine. After using it to make some parts for the robot we were building, the technician brought out a cassette tape (the code was stored on tapes) and pushed it into the machine. He hit go and the machine started to play music! The cool thing was that it was using the stepper motors of the table to form the notes by spinning at different frequencies.
I wanted to replicate this on the Makerbot and I found some sample code from here that had what I was looking for. Unfortunately, it didn't work for the Makerbot so I had to hack it. This resulted in Tetris Music!