Right before Numbuh 5 is about to destroy the Queen Lice, Numbuh 2 interrupts them and says she needs to deliver a Pre Ass Kicking One Liner
Numbuh 2: WAIT!!! You gotta say a really cool line first! Like "Say cheese, punk!" or "Cheese to meet you!" Wait, wait, wait! How about this—(Numbuh 5 presses the button as the Queen Lice is distracted) Cheese—(Cut to a scene of the Treehouse and a giant melted cheese explosion)
Bonus points for Five and the Queen Lice giving each other a "what the heck is wrong with this guy?" look right before Five pushes the button, and Two being covered in baby lice.
Numbuh 86: Of all the stupid things in the stupid world of stupid people acting stupid, you boys are the stupidliest! It's like you're trying to win a stupid contest but you're too stupid to take a stupidity test!!
What's even funnier is that Numbuh 86 finally gets her comeuppance for antagonizing Sector V for the duration of the episode.
Number 86 spazzing out during the incident with the toenail collection.
And even before she gets covered in them and completely loses it, we get this gem:
Numbuh 86:(voice wavering) Whu-what's that? Delightful Children: It's... our toenail collection. Numbuh 86: Toenails? (gags, sputters, otherwise flips out) That's disgusting! Delightful Children: It is not! It's more like... a hobby.(laugh evilly as they close in on Numbuh 86)
As Numbuh 86 goes on a tirade, Numbuh Four whispers to Numbuh Two: "Man, who put a bee in her undies?" Near the end of the episode...
"Hey, Fireface! Looking for this Code Module thingy?"
Not to mention that Father finds out it's an autograph book, and is impressed on it having Numbuh 362's autograph.
Numbuh 60: Any questions? Tommy: Oooh, I have one! I know Numbuh One! And Numbuh Two is my brother! I even have all their autographs from when I went on a mission with them! Numbuh 60:(facepalm) That is not a question, Tommy.
Every time Father bursts into flames, the ice above him melts and splashes him. Helps to turn that power of his into Nightmare Retardant.
Two of Father's henchmen threaten to put Tommy, Lee and Sonia into a broom closet. Cue Sonia freaking out and Tommy and Lee shivering in fear as she beats the two guards into submission.
Wally:(as Kuki is crying on Hoagie's shoulder) And would you mind hugging your own wife instead of mine?! Hoagie: Hey! You're not Abby!
Also, Numbuh One seeing the giant toilet in the Delightful Children's bathroom.
"So that's how they go together!"
The Empire Strikes Back parody in "Operation: S.N.O.W.I.N.G.". Especially because A) 4th grade President (of Gallagher Elementry) Jimmy plays the part of Darth Vader, and B) they actually find Luke Skywalker.
In a comic book, this is referenced by, when Numbuh 86 is partially decommisioned when she turns on one of the machines, and goes boy-crazy in the process, and one of her officers questions why the machine would zap the person who turned it on. Another officer responds that the guy who made the "Blow-Up-The-Engines" button on all KND spacecraft worked on this machine, and says they really should get rid of that guy some day.
Sweet merciful Numbuh Zero, "Operation: S.I.T.T.E.R.". Just... "Operation: S.I.T.T.E.R.". Numbuh Two tries to seduce Cree.
Made even funnier when you remember that as cheesy as all the bad French he uses sounds to us, it must have been even worse for Cree as she herself is half-French.
Cree:(blankly stares, then facepalm) This is so not worth 8 bucks an hour.
Tommy: I don't wanna go to bed yet! You can't make me! Cree:Oh, I applaud your braver— (clapping activates disco ball) THAT'S IT!
Numbuh Four: Listen Numbuh Five... I... I don't wanna fight you! Zombified Numbuh Five: I know! Cause you're the weakest, shortest, dumbest, most chicken, big mouth squirt on the whole team!! Numbuh Four:(raging) OKAY! NOW I WANNA FIGHT YOU!
Numbuh Four: Hey Spankaholic! Time to teach you the Australian word for "ouch"! Count Spankulot: Ridiculousness! Those who fail to realize that the Australian word for "ouch" would still be "ouch" will be— (Numbuh Four pulls out a gun that SHOOTS A KANGAROO) Spankulot:(beat)Is that a kangaroo?
Numbuh One turning into a total fanboy when he realizes that his father used to be the legendary Numbuh Zero.
After sector V drops the moonbase on grandfather, we see that Father's mansion was destroyed in the explosion as well. Father has this to say about it.
There's also his "He's Back" moment. After getting the short end of the stick from his father for nearly the whole movie, he finally loses his patience with everything. Only to resign himself to everything that's happened and stroll off to eat some ice cream.
Father: You... big...JERK!Now you've made me angry. VERY. VERY.VERY...ah, forget it.
While they do serve as terrifying most of the time, some of the lines of the Delightful Children from Down the Lane are pretty damn funny.
For example: "Hello Kids Next Door. Perhaps you would like to try kicking our posteriors now?"
Mr. Boss: So long, kid! I hope your friend likes Pluto! (entire building crashes on top of him)
From "Operation: R.A.B.B.I.T.":
Numbuh Two:(upon seeing the desolate First Grade hallway) Man, those school budget cuts are murder.
At the end, when returning the Frist Graders pet rabbit restores them...
Numbuh Two: But man, I'm so hungry, it's not even bunny!(Starts to laugh until Numbuh Five hits him for making that joke)
The entire KND is having a worldwide game of tag, with the person who is "it" at the end of the game becoming the next Soopreme Leader. Everyone is trying their hardest to avoid being "it" at the end of the game... right up until someone accidentally tagsNumbuhThirteen. Cue the dogpile.
Bonus points that he was the only operative besides Father excited to get the position.
Numbuh Thirteen: HOT DOG! I'm gonna be the leader of the Kids Next Door! Operative: OH NO YOU DON'T! (dogpile)
In "Operation: L.O.V.E.", which musical fans will recognize as a spoof of West Side Story. Let's count the ways:
'50s' style costumes (including Numbuh One wearing tacky 3D glasses).
The reveal that Numbuh One has a big butt and all the joke puns everybody makes at his expense.
Number Five challenges Stickybeard to a sugar swallowing contest. When Stickybeard decides to not do so, she replies "Unless you're... sugar-free." Cue all the pirates going "Oooh..."
That same quote gets an Ironic Echo when it's revealed that Stickybeard was a cabin boy to legendary Black Licorice Pirate Old John. The undead pirate laughs in the face of the challenge so Stickybeard goes, "Unless ye be...sugar-free."
Licorice Pirates: Oooh..."
Even better, Numbuh Five takes his place in the sugar swallowing contest and ultimately spazzes out. Then, after defeating Black John once and for all, Stickybeard pours some sugar for he and Numbuh Five to partake in. Numbuh Five collapses into a sugar coma.
"Operation: G.R.A.D.U.A.T.E.": We get to see the Delightful Children turned into sheep. Sheep that look like the one in Sheep in the Big City, no less!
Numbuh Five tells everyone not to do anything that will wake Numbuh One up. They all silently agree, then walk quietly over to the sofa, then Numbuh Two turns on the TV...
Announcer: MONSTER TRUCK RALLY! DO YOU LIKE MONSTER TRUCKS? LOUD MONSTER TRUCKS? THE LOUDEST MONSTER TRUCKS THIS SIDE OF LOUDSVILLE!
Made even funnier by the fact that Numbuh Two loses the remote the second the TV comes on.
This bit from "Operation: P.I.A.N.O.", after Numbuh Four botches the mission to destroy the Type-P torture device:
Numbuh One: Okay, Kids Next Door. Simple question. What did we learn today?
Numbuh Two: Do not deviate from plans.
Numbuh Five: Teamwork is the key to mission success.
Numbuh Three: Operational procedures are important.
Numbuh Four: (in a wheelchair and covered in bandages) Pianos...are heavy.
Numbuh One: Oh, close enough.
The KND manage to destroy all the pianos before Numbuh Four screwed it up...except for the very piano that was meant for him.
Numbuh 4: Kuki, I-I'm scared. I don't know what to do next!!
Numbuh 3:Kiss me!
Numbuh 4:Kiss you?! No way! Oh, nonononononono! Nu-uh! Nope, no way! Ain't gonna happ- okay.
"CRAZY 80'S 2X4 SUPER-STORE!" is a barrelful of laughs (Fart ID spray, the Jelly-O-Matic spraying the scientists with bean residue ("Twenty percent of the time, still working out the kinks out on that one...), and the Teacher-Canceling Headphones.
Father is without a doubt one of the Kids Next Door's most dangerous foes. With his fire powers, he's a Person of Mass Destruction...unless he goes off around something that reacts to intense heat, like popcorn (M.U.N.C.H.I.E.S.) or ice (.T.R.A.I.N.I.N.G.) or cake frosting (C.A.K.E.D-.F.I.V.E.). Then, Hilarity Ensues.
In the flashback beginning of Operation: M.A.U.R.I.C.E., Numbuh 9, the titular Maurice, is making a passionate vow to find the Teenz' source of Chicken Pox when his mother comes in with cookies for him and the Kids Next Door.
Numbuh 9: Mooom! I'm in the middle of a life-defining speech here!
The Creative Closing Credits used in the 4th season onward, showing a little sketch while the credits run, are always good for a laugh in some episodes.
After C.L.U.E.S., Numbuh 2's grandma Lydia is going through the fridge, looking for something to eat while grumbling; "What am I craving? A man with a job. Haha, I crack myself up...!"
From the earlier episode F.U.T.U.R.E., the credits featured Madame Margaret destroying her Girlifyer Ray... synchronized to the ending theme song.