Although it isn't really obvious, there are some good applications for this stuff. Think of how sound gets dampened in a forest. Perhaps if we listened to some noise being blasted into the forest from outside we can determine the percentage of foliage, the hardness of the ground, and the thickness of the tree trunks. Likewise, corn farmers could learn more about their crops using such a system. By the way, the guy pretending to be working on my experiment was one of my high school assistants. He wasn't wearing a Pink Floyd t-shirt and shorts that day.
Later I worked on an acoustic motor -- when the volume is turned up, a cup placed in the box on a pin would begin to rotate. Supposedly, the effect is not caused by any streaming of the air which would drag the cup into motion, but no one is completely sure of this yet.
I also tutored sophomore physics for a while, but eventually got tired of missing Sienfeld for a measly five bucks. The last semester I was there I went freelance at ten an hour, and actually had three or four steady clients.