Chalkboard: I will not celebrate meaningless milestones

Couch: The Simpsons sit on the couch just as the FOX station identification bumper comes on. Homer spots it, gets up, peels it off, and stomps on it (along with the rest of the family).

Even though this episode is broadcast as the 100th episode, the 100th episode (according to production code) is the season 6 episode "Lisa's Rival".

Lisa: I think you need Skinner, Bart. Everyone needs a nemesis. Sherlock Holmes had his Dr. Moriarty, Mountain Dew had its Mellow Yellow, even Maggie has that baby with the one eyebrow.

Superintendent Chalmers: You're fired!
Skinner: I'm sorry, did you just call me a liar?
Superintendent Chalmers: No I said you were fired.
Skinner: Oh. That's much worse.

Principal Skinner: Now I... I finally have time to do what I've always wanted: write the great American novel. Mine is about a futuristic amusement park where dinosaurs are brought to life through advanced cloning techniques. I call it Billy and the Cloneasaurus.
Apu: Oh, you have got to be kidding, sir. First, you think of an idea that has already been done. Then, you give it a title that nobody could possibly like. Didn't you think this through-- (passage of time) --it was on the bestseller list for eighteen months! Every magazine cover had-- (passage of time) --most popular movies of all time, sir! What were you thinking?!! (pause) I mean, thank you, come again.

Bart: Boys and girls, Mrs. Krabappel, I come before you today to solve a riddle that has plagued mankind for centuries: What has four legs and ticks?
Milhouse: A walking clock?
Nelson: A walking clock!
Martin: I'd wager he has some variety of walking clock in that box!
Edna: Bart, is it a walking clock?
Bart: What?.....No, it's my dog.