While Francis is in the diner, you can see Dewey in the background on the television screen (upper left of the screen) on what appears to be a news broadcast that says Toxic Orphan.
In a flashback scene, Francis says "Now we know, pigs can swim, cows can't". Cows can, in fact, swim.
Hal: Is that pepper spray?
Cadet Edwards: I also have a whistle and I'm prepared to use that as well.
Malcolm: What are you gonna do? Spank me?
Lois: Okay. (grabs Malcolm and spanks him lightly, Malcolm is embarrassed)
Reese: I guess when people are miserable and suffering, it brings out the best in me.
Malcolm: We could all die!
Lois: When that happens, you're off the hook. But until then, I want those buns on that cot.
Reese: That'd be so cool! "My name is Reese, what are you lookin' at?"
Reese: Mmm, ice cream. What a wonderful unexpected treat, for SOME of us.
Malcolm: Yes, Reese. You get ice cream and I don't. Thank you for subtlety illustrating that point.
(door bell rings)
Hal: I'll get it.
Reese: Mmm, sprinkles. Aren't those you're favorite, Malcolm?
Malcolm: I'm rubbing my butt on your pillowcase.
(the family tries to get Malcolm's attention)
Malcolm: I can't. I'm not supposed to leave my cot.
Dewey: I can smell colors!
(Dewey and Hal are driving to dump, singing to the tune of "A Partridge in a Pear Tree")
Dewey & Hal: When we get to the garbage dump, this is what we'll see.
Dewey: Five broken toilets.
Hal: Four flaming cheeseburgers.
Dewey: Three fat maggots.
Hal: Two giant rats.
Dewey & Hal: And a stench that will buckle your knees.
Police Guard: If I wasn't in full uniform I'd take a swing at you myself.
Hal: Now you two are going to apologize for what you have just done.
Dewey: We're sorry we left the couch on the tracks and broke the train.
Person: Oh for the love of God.
Man: This is ridiculous. The man before me didn't have to pay this much.
Reese: It's a cold, hard world. It's getting colder by the minute.
Man: (rips watch off) You're an evil, little punk.
Reese: (shakes finger in what man just said) Uh, uh. Now it's socks, too.
Lady with Chocolate: I'd be happy to give you some, but you should really ask your parents first.
Dewey: I can't. They're dead. They were killed by the cloud. Can I have some?
Cold Open: The boys have Dewey try to beat a record of riding the washing machine spin cycle like a mechanical bull.
First time ever that Malcolm one-ups Lois, as her and the rest of the family is stuck outside while he remains inside while still "grounded."
Reagen Dale Neis would later appear in year four as Nicki, Malcolm's sociopathic girlfriend.