Chalkboard: Fish do not like coffee

At the end of the episode, Homer states that Maggie no longer has to uphold her siblings. She was holding Bart and Lisa's signature items, the skateboard(Bart) and the saxaphone(Lisa).

Couch: In a parody of the opening of the 1960s sitcom, Get Smart, Homer goes through many futuristic doors and passageways until he reaches the phone booth, dials a number, falls through the floor, and lands on the couch (with the rest of the family already seated).

Bart: I'm sorry I sabotaged your flag.
Lisa: Well, I'm sorry for getting us lost out here.
Bart: I'm sorry about the time I sawed the heads off your Malibu Stacies. You go.
Lisa: I don't think I have any more.
Bart: That's okay, I'll go again. Remember the time your bike was mangled by Gypsies?
Lisa: Yes . . .
Bart: Funny story. I was bored one day, and Dad had left his steamroller idling in the driveway . . .

Bart: Quiet nerds burp only near school.
Lisa: Bart, I'm doing my geography homework.
Bart: I know. That's how you remember the 4 original provinces of Canada. Quebec, New Brunswick, Ontario, Nova Scotia; quiet nerds burp only near school. And here's how you remember the principle exports; dogs eat barf only on Wednesday, Mable.
Lisa: Stop! I want to learn on my own.
(Bart walks out of the room)
Bart (hanging from a vent): Canada's govener's general; clowns love haircuts, so should Lee Marvin's valle.
Lisa: Get out! (attempts to hit Bart with her book)

Skinner: If this episode has taught us anything, it's that nothing works better than the status quo. Bart, you're promoted back to the fourth grade.
Bart: Yeah!
Skinner: And Lisa, you have a choice. You may continue to be challenged in third grade, or return to second grade and be merely a big fish in a little pond.
Lisa: Big fish! Big fish!
Homer: The status quo.
Milhouse: The status quo? Ay karumba!
Skinner: That's just sad.