In the first episode, while Ringo and Ryoko are in the bath, the narrator comments for the third time about their lack of endowment. This proves to be the proverbial straw that broke the camel's back, and Ringo and Ryoko punch the narrator.
The first time the narrator comments on her.... size in the english dub is pretty funny as well.
Narrator: "Unfortunatly, the "Flat-Chested Wolf" and "Little Red Riding Twerp" are this show's eye cand-"*Ryoko glares at the Narrator* "Ehem, heroines."
Most of what the narrator says qualifies for this, particularly in the dub. Possibly the funniest is when she gets fed up with the recurring term for Momoko's rack.
"Is 'dumplings' too subtle a metaphor? BREASTS!"
In Episode 7, when Ryoko gets amnesia and Ringo asks Ryoshi what's going on.
Narrator: Nothing over here! Just a whacked-out time warp date thingy. No big! We'll talk later.