Otto: Distinguished guests, friends, members of the press... when the Fish Defense League told me that the dam on our property was blocking the endangered silverback trout from its natural breeding grounds, I was glad to help. And so today, we are going to blow up this evil dam. Afterwards, we will have a nice, light lunch provided by the Grotto, a friend of fish and the business traveler. Here we go!
Francis: That's weird. From here, the dynamite looks a lot like a picnic cooler.
[When Otto presses the ignition key, a flat-bed truck behind them goes up in flames]
Otto: I am starting to think that that is a picnic cooler.

Dewey: So the school thinks I might be a genius, too? But I'm not a whiny loudmouth who complains about everything.
Reese: Malcolm's a genius, and now Dewey's a genius? I guess it's only a matter of time 'till we find out that I'm a genius. I wonder what kind of genius I am. 15 times 32 is 3,989.
Malcolm: It's 480.
Reese: Okay, so I'm not Rain Man, big deal. Some day they'll invent a machine that does that stuff for you, anyway.

Lois: [cutesy voice to Jamie] ...and then he was chopped up and eaten by wolves, because that's what happens to babies who pull hair.

Malcolm: Okay, question 17 was, "Bee is to hive as A) fish is to pond, "B) bear is to den or C) coral is to reef?" That's what it was, right?
Stevie: How should... I know?
Malcolm: You took the same test I did.
Stevie: Four... years ago. How do you... remember?
Malcolm: I just do. And it's a good thing, because it's the only way we can keep Dewey out of the Krelboyne class.
Stevie: Why can't... he just... tank it?
Malcolm: The tests are designed to catch that. We have to give exactly the same answers a real dumb person would give.
Stevie: How do we... do that?
Reese: [enters] Guys, guys! I've been trying to figure out what kind of genius I am, and I finally realized, I should go to the library! And you know what? You can get Internet porn there and the librarians can't do anything about it! God, I love this country. [Malcolm and Stevie smile at each other]

Craig: Ow! Ow! My ankle's twisted. Once again, I fly too close to the sun.
Hal: But we have to dance.
Craig: I can't, Hal. But you have to go on. We've worked too long and too hard to stop now. Go out there and win that coupon for two free medium pizzas for both of us.

Malcolm: [to camera] Mom and Dad let Dewey pick where we went to dinner tonight. I can't decide if it's supposed to be a punishment for us or a treat for him. Probably a little bit of both.

Lois: So, Dewey, are you having a good time?
Dewey: I actually am. Oh, wait. Why?
Reese: He's dying! We have to make sure you come up with a really good wish.
Hal: Reese, he isn't dying. If he were dying, we'd at least spring for Red Lobster. [chuckles]

Lois: Mrs. Welsh, your counselor, said that she'd like you to take an I.Q. test.
Malcolm: What?!
Lois: Malcolm, do not poison your brother. He is an entirely different person than you are and he is not automatically going to have the same experience! It's just a little test, honey.
Malcolm: Mom, don't do this. I lost all my friends when I went into the Krelboyne class. Everyone hated us!
Lois: You had every advantage in that class. You had computers, an electron microscope, a seismograph...
Malcolm: Which is why they hated us!
Hal: Malcolm, we all know there's something weird going on in that boy's brain and I, for one... [gets distracted by the dance machine]

Craig: I think we're finally ready. I didn't want to say anything until I was sure, but I signed us up for the weekly tournament.
Hal: No, it's too soon.
Craig: Hal, you don't work this hard just to Jump Jump Dance alone in your room. Besides, someone has to teach Hayley and Kylie not to be so stuck up just because they think they're so great.
Hayley: You can't enter the tournament. You're going to look like idiots.
Hal: We're not done rehearsing. We'll be a lot better by then.
Kylie: No, you're going to look like idiots because it's a contest for kids.
Craig: It doesn't say that anywhere. I read the rules three times. And we're under the weight limit. You can call the manufacturer.

Malcolm: If you give these answers exactly the way they're written, you'll stay out of the Krelboyne class.
Dewey: Maybe I'd like the Krelboyne class. I hear they just got a robot parrot that speaks 20 languages.
Malcolm: Dewey, you have to trust me. I'm the good brother. I'm the one who cares about you.
Dewey: You beat me up and make fun of me.
Malcolm: Only when you're being annoying. Dewey, I'm serious. How can I make you understand? The coolest person in the class... was me.
Dewey: Okay, I'll do it.
Stevie: You're sure... this'll work?
Malcolm: Hey, if there's one thing I know, Reese's answers will not get him into the Krelboyne class.