I looove "Ouch, They're tight!" because whomever it is has Daphne's vocal inflections down pat. I always crack up at "So I'll use this BAR, and hump it like some porno star!"
Actually, all the RENT parodies are pretty spot on.
But I think "Chita-Rita" or "Liza-One Note" are my favorites of all time.
"Who says you can't bend over backwards and eat bugs if you want to? I guess the bugs would probably say you can't do that that, but assuming that they are willing and consenting bugs, then there's no problem. Let's wig out eating bugs."
-RuPaul