A "practical" use
Back in the day, the 1401 jockeys on the business side of the "computer center" (A porta-shed) got a program to play music via RFI modulated by the length of data in "MOVE" instructions. Not to be outdone, the 1620 pilots on the "engineering" side reverse engineered the code, ported to the 1620, and added a percussion section, issuing appropriately timed "seek" commands.
It may help to know that these were all community-college students, with a certain amount of youthful enthusiasm. And spare time...
(The practical side I have mentioned before. Having a reliable "audio signature" to track the behavior of the code allowed us to leave the machine room for next door while a longish task was running, secure in the knowledge that the distinct whine of the "waiting for next console command" state would cue us to put our parkas on and go start the next job.)
For completeness (sound from unexpected computer systems) I must mention Ken Shirriff's blog entry about using a printer for music: