Mrs. Krabappel: Now I don't want you to worry, class. These tests will have no effect on your grades. They merely determine your future social status and financial success. [She looks at Bart.] If any.
There's No Disgrace Like Home - S1-E4
Homer: Sometimes I think we're the worst family in town.
Marge: Well maybe we should move to a larger community.
$pringfield (or How I Learned to Stop Worrying and Love Legalized Gambling) - S5-E10
Bum: Got any spare change, man?
Grampa: Yes! And you ain't gettin' it! Everybody wants something for nothing. [He walks into the Social Security Office.] I'm old! Gimme gimme gimme!
The Two Mrs. Nahasapeemapetilons - S9-E7
Apu: Okay, quickly, what is your favourite food, book and movie?
Manjula: The answer to all three is 'Fried Green Tomatoes'.
And Maggie Makes Three - S6-E13
[Maggie is being born.]
Homer: Aw, it's a boy! And WHAT a boy!
Dr Hibbert: That's its umbilical cord. It's a girl.
Tree House of Horror VI - S7-E6
Homer: Please, don't eat me! I have a wife and kids! Eat them!
Tree House of Horror IV: The Simpson's Halloween Special IV - S5-E5
[Homer runs naked through the kitchen, where Patty and Selma are eating.]
Patty: [after seeing Homer.] There goes the last lingering thread of my heterosexuality.
Homer: Kids, you tried your best and you failed miserably. The lesson is, never try.
Blood Feud - S2-E22
[Homer goes to the post office to get a letter he accidentally sent to Mr Burns.]
Homer: [In an obviously fake voice.] Hello, my name is Mr Burns. I believe you have a letter for me.
Post Office Clerk: OK, Mr Burns, what's your first name?
Homer: I don't know.
Comic Book Store Owner: Now make like my pants and split!
'Tis the Fifteenth Season - S15-E7
Krusty: So, in the spirit of the Christmas season, start shopping! And for every dollar spent on Krusty merchandise, I will be nice to a sick kid. For legal purposes, sick kids may include hookers with a cold.
Brother From Another Series - S8-E16
Bart: Inside the body of every hardened criminal beats the heart of a ten-year-old boy.
Lisa: And vice versa.
22 Short Films About Springfield - S7-E21
Principal Skinner: Well, that was wonderful. A good time was had by all. I'm pooped.
Superintendent Chalmers: Yes, I should be — Good lord, what is happening in there?
Principal Skinner: Aurora Borealis?
Superintendent Chalmers: Aurora Borealis? At this time of year? At this time of day? In this part of the country? Localized entirely within your kitchen?
Principal Skinner: Yes.
Superintendent Chalmers: May I see it?
Principal Skinner: No.
Agnes Skinner: Seymour! The house is on fire!
Principal Skinner: No, Mother, it's just the Northern Lights.
Homer: If you really want something in this life you have to work for it. Now quiet, they're about to announce the lottery numbers.
Answer: I'm not sure if this is the one you're thinking of, but an episode of "Ray Bradbury Theatre," called "A Sound of Thunder," dealt with a similar matter: a group of hunters travel back in time to hunt dinosaurs, only to find things have changed when they get back because someone stepped on a butterfly.
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