Hi,
You don't hear much of it anymore but one of the nicest things in the late 60's and 70's on the FM radio was a bunch of people playing around with the albums and needles ... and of course speeding things up or down was one of the major things. And in LA, there were several DJ's that were known for playing around with these things and then some, and even the likes of the Firesign Theater made their fame off a lot of those situations along with clever radio trickery since they were all dj's or actors.
Nowadays, you do not see that fun side of things anymore. The Chipmunks are not even funny when compared to so many other things ... but they are a novelty for this generation that has not heard it.
I've mentioned many times some backwards stuff here, because my roomie was known for sound effects and fun, and there isn't a single sound effect in the 25 LP's of the original BBC Library of sound effects for radio that was not played backwards and at different speeds. But saying that here ... nobody believes it, and I have recordings of it! It's Mosh just spewing!
NP: Supersister (Craig will know!)