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.
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.