From David Bowie's song Changes, which played at the opening of the movie.

And these children that you spit on

As they try to change their worlds

Are immune to your consultations

They're quite aware of what they're going through

Andrew (Emilio Estevez): We're all pretty bizarre. Some of us are just better at hiding it, that's all.

Bender (Judd Nelson): Hey, how come Andrew gets to get up? If he gets up, we'll all get up, it'll be anarchy.

Bender and Claire (Molly Ringwald) are talking about school social hierarchy, and Brian (Anthony Michael Hall) keeps interrupting.

Bender: Excuse me a sec. What are you babbling about?

Brian: Well, what I had said was I'm in the math club, uh, the Latin, and the physics club ... physics club.

Bender: Hey, Cherry. Do you belong to the physics club?

Claire: That's an academic club.

Bender: So?

Claire: So academic clubs aren't the same as other kinds of clubs.

Bender: Ah ... but to dorks like him, they are. What do you guys do in your club?

Brian: Well, in physics we ... we talk about physics, properties of physics.

Bender: So it's sorta social, demented and sad, but social. Right?

To Mr. Vernon (Paul Gleason) ...

Bender: Does Barry Manilow know that you raid his wardrobe?

Allison (Ally Sheedy) talks to Andrew.

Allison: Your middle name is Ralph, as in puke; your birthdate's March 12th; you're 5'91/2; you weigh 130 pounds; and your Social Security Number is 049-38-0913.

Andrew: Wow. Are you psychic?

Allison: No.

Brian: Well, would you mind telling me how you know all this about me?

Allison: I stole your wallet.

The janitor, Carl (John Kapelos), talks to the kids.

Carl: I am the eyes and ears of this institution, my friends.

Bender and Claire have just kissed.

Bender: Remember how you said your parents use you to get back at each other? Wouldn't I be outstanding in that capacity?

At the end of the movie, a voiceover reads the essay the students were supposed to write during detention.

Brian: Dear Mr. Vernon, we accept the fact that we had to sacrifice a whole Saturday in detention for whatever it was we did wrong. What we did was wrong. But we think you're crazy to make us write an essay telling you who we think we are. You see us as you want to see us ... in the simplest terms, in the most convenient definitions. But what we found out is that each one of us is a brain ...

Andrew: ... and an athlete ...

Allison: ... and a basket case ...

Claire: ... a princess ...

Bender: ... and a criminal.

Brian: Does that answer your question? Sincerely yours, The Breakfast Club.

SOURCE: IMDB.COM