Prof. Farnsworth: Your grandfather?! Stay away from him, you dim-witted monkey! You mustn't interfere with the past! Don't do anything that affects anything, unless it turns out you were supposed to do it, in which case for the love of God, don't not do it!

    Prof. Farnsworth: For example, if you killed your grandfather, you'd cease to exist!
    Fry: But existing is basically all I do!

    Prof. Farnsworth: Start the ship, Leela! Let's just steal the dish and get back to our own time.
    Fry: But won't that change history?
    Prof. Farnsworth: Oooh, a lesson in not changing history from "Mr. I'm-My-Own-Grandpa"!

    President Truman: Whistlin' Dixie! I want this sent to Area 51 for study.
    General: But Sir, that's where we are building the fake moon landing site.
    President Truman: Then we'll have to really land on the moon! Invent NASA and tell them to get off their fannies!

    Leela: Oh, I'm sorry. Now I'll axe you again. Where is the mi-cro-wave?
    Salesman: Sir, your wife is hysterical, so I'll address this to you. This oven is lighting fast. It only takes five hours to cook a pot roast.
    Prof. Farnsworth: Ooh, that's good news! You know, you don't cook enough roasts, Leela.
    [Leela turns on stove, setting the Professor's tie on fire]
    Prof. Farnsworth: [to salesman] Women!

    General: What's your purpose?
    Zoidberg: Alright, officer, I'll move it along.
    Military Official: What the general means is, why did you come to Earth?
    Zoidberg: Not a day goes by I don't ask myself the same question.

    Leela: Well, settle in. Without a microwave, we're stuck in this time period.
    Prof. Farnsworth: Oh, Lord! We'll have to endure the horrible music of the Big Bopper, and then the terrible tragedy of his death.

    Bender: Fry, stop interfering with history! I don't wanna have to memorize a lot of new kings when I get back.
    Fry: I had no choice. I was about to not exist. I could feel myself fading away, like Greg Kinnear.

    Fry: She sure is pretty. You ought to marry her and father some children right away.
    Enos: Yeah, folks say that. But did you ever get the feeling you're only going with girls 'cause you're supposed to?
    Fry: What?! Don't ever, ever say or think that again!

    Bender: [after Fry accidentally kills his grandfather] And you...are...outta here!

    Prof. Farnsworth: What the hell have you done, Fry?
    Fry: Relax! She can't be my grandmother. I figured it all out.
    Prof. Farnsworth: Of course she's your grandmother, you perverted dope! Look!
    Mildred: [wearing glasses and knitting] Come back to bed, deary.
    Fry: [screams] It's impossible! I mean, if she's my grandmother, who's my grandfather?
    Prof. Farnsworth: Isn't it obvious?
    [Fry shakes his head.]
    Prof. Farnsworth: You are!