"We love Meathead!" sign
Kenny eating his own hand
"My goo, my precious goo."
Cartman says, "Thought you had me with your Serbia Jew double bluff, didn't you?"
the way Rob Reiner melts and says "My goo! My precious goo!" is a parody of the Wicked Witch of the West melting
The cheerful workers in the cigarette factory and the song they sing
"I'm Rob Reiner and you've just been Reinered!"