Bret's music for The Muppets is full of meta hilarity.
Series:
Most anything Dave says but especially: "It's not a fucking school play production. It's the bird." (Dave to the guys when trying to show them how to flip someone the bird).
This is one of the best:
Sinjay (threatingly): I'm going to count to 10!
(awkward silence)
Jemaine: Are you counting in your head?
Sinjay: Yes.
Jemaine: What number are you up to?
Sinjay: Seven.
(Jemaine and Bret run away)
Murray telling the guys about when he was in the New Zealand army, while in fort they made in their bedroom.
Murray: And one time... my whole platoon had to drink their own urine.
Bret: Oh, were you lost?
Murray: No, we were drunk. It was a party game. I didn't really like that part of the army. More tea, Jemaine?
Or Murray lambasting Jemaine for dating an Australian:
Murray: What about your kids, Jemaine, did you think of that? They'd be aberrations!
Jemaine: Actually it's pronounced Aborigine.
Murray is famous for stealing just about every scene he's in, but he makes the episode in "What Goes On Tour":
