Not in a managed classroom environment, to be clear. I'm talking about just on your own when you were sitting around by yourself. For me it was this... I had a Sony Walkman. What I did was push play (recall that how that worked back then was that when you pushed the record button, the play button also pushed down with it) but I did not insert a blank cassette into the player. Then what I did was I barely plugged the 3.5mm headphone end into the jack. Just to the point that it barely connected. It didn't click, I had to hold it there in a zero pointish type position. Given that there was no cassette in the player, the magnetic mechanism (a two part mechanism) that the tape would normally run across/through magnified the sound of everything around me. And in the 432 hz, no less. I was amplifying the universe itself. I was like wtf? You?