favorite vocal/song parody
I'm thinking of the fake made up songs that are Matt or Trey doing an impersonation of a famous singers voice. My favorite may be from the S2 episode Conjoined Fetus Lady, where there is the song that is clearly supposed to sound as if Neil Diamond is singing it.
https://www.youtube.com/watch?v=AUvRDHHvkRc
Another good one is from Cartman's Mom Is A Dirty Slut, with the little nod to "My Heart Will Go On" that you hear whenever the young Mrs. Cartman sees a new guy at the drunken barn dans.
There you are, like a throbbing star...
What are your favorites?