I can name a few:
S: The question is, what exactly is a mahna-mahna?
W: The question is, who cares!
W: Where is the land of the rising sun?
S: I don't know, I never get up that early!
W: We look like members of the rock age!
S: No, we look more like members of the stone age!
This one needs some explaining: at the end of the cluckitis episode, Statler and Waldorf show up as (I think) badgers.
S: I suppose you were expecting chickens!
W: yeah, woof woof!