Kat --No, there were no parodies right after 9/11. But there were many responses to the tradgedy in song (I myself wrote one): musical expressions of the grief, anger, hopes for healing, disbelief, shock.
Granted, some were not very good (all of those emotions translate well into art, I think except disbelief and shock). But the urge to sing comes with the feeling of deeep emotion. I sometimes wonder if the human capacity for song has its roots in the howl, which evolved before the use of words.
Who says a song challenge has to be funny?!!