The "sisters" who lived together, who were clearly a gay couple. They were called "Miss Tutti" and "Miss Frutti".
The ham costume scene from the pageant, anyone?
Scout's reaction to the "nigger snowman." You laughed, admit it. Said snowman was made to look like Scout's grumpy neighbor, Mr. Avery - anatomically correct.
Atticus: I don't care what you do, so long as you do something. You can't go around making caricatures of the neighbors.
Jem: Ain't a characterture. It looks just like him.
For the record, the snowman scene is even funnier if you're from Alabama, which to this day rarely gets more than a half-inch of snow. Kids still scour the neighbors' yards to gather enough material for a decent snowman, and the sight of a sad, skinny snowman standing alone in a muddy, bare yard is a common one.
When the lynching mob shows up in the middle of the night, Atticus tells them not to wake Tom up. For the rest of the scene, the mob talks in whispers.
Scout's reaction to it snowing - she thinks the world is ending.
Scout practicing her cussing. Pass the damn ham, please.
I was proceeding on the dim theory, aside from the innate attractiveness of such words, that if Atticus discovered I had picked them up at school he wouldn’t make me go.
Scout misunderstanding the concept of double-first cousins. "I tortured myself and decided that if I married Jem and Dill had a sister whom he married our children would be double first cousins."
Dill's foolproof plan to draw Boo Radley out: place a trail of lemon drops from his back door to the front yard.
In the courtroom scene:
Mr. Gilmer: Are you ambidextrous, Mr. Ewell? Bob Ewell: I most positively am not. I can use one hand good as the other.
"Mr. Ewell, you will keep your testimony within the confines of Christian English usage, if that is possible."
"Let the record show that the witness has not been sassed."
Jem's pants get caught on a fence when he, Scout, and Dill run from a gun shot. When Atticus, in front of an entire crowd of Maycomb adults, asks Jem where his pants are, Dill says he won them in a game of strip poker.
When Dill sneaks back to Maycomb:
Scout: How'd you get here?
Dill: *spins an elaborate tale of being cruelly confined, managing to escape and walking miles and miles to Maycomb*
Jem: How'd you get here?
Dill: *coughs up the real story without so much as a protest*