It seems as if the idiots have been re-dubbing various air guitar sequences, and most notably - the JEOPARDY theme!
Listen to tonight's episode, and then a tape of the first time it was played. They took the notes, and moved them around! I bet the Jeopardy people threatened to sue or something equally stupid.
It's hard to tell exactly what is happening to the other air guitars, but they sound a lot louder and squeezed together than the original. I first noticed when I went to do it along with the TV on a fairly old episode (Babes R Us, after scene w/ Daria) and ended up _not_ matching up with them when I'm normally right on track.