When Amu copied "Yaranaika?" upon seeing Tadase in a skirt. And the anime somehow makes that scene even funnier.
When Amu and El transform, and Amu tries to fight using El's power. She gets stuck with a flag of surrender.
It got funnier at the final battle against Utau... WHITE FLAG DOUBLE PLAN!
Amu and the gang dressing up in Christmas themed costumes!
During the athletics competition, a competitor gets injured. Amu looks around for someone who can replace her. One bombastic reaction later we're treated to the sight of Rima wearing comically oversized sunglasses, sipping a drink and being waited on by her entourage of fanboys. Rima's demeanor just says "Like A Boss!"
Episode 21. Oh sweet Heart's Egg. At one point during the episode, while Amu tends towards the house while her parents and Ami are out - side, a package arrives. They take it towards a kitchen table, open it... And see that it contains a live crab. After some cautious behavorial experiments with it, it captures Miki within it's claw. What happens next is an imagine spot which is essentially sort of kind of like a childish version of Excel Saga: The crab becomes extraordinarily large, with Miki, within her usual size, still within it's grasp. As well as this, rather than residing within a box on a table, it is currently seemingly assaulting a city. Ran, within a a typical "broadcasters" suit, reports upon the incident towards a camera, while Amu and Su, within standard military camo, pilot a tank trying to take the crab down. It, much like much of Excel Saga, is so bizzare it's hilarious. They eventually rescue her through - out use of a plunger, although they "offend her artistic sense" within the process. Also, Funny Aenurism, as Miki, as well as all of Amu's current Chara, are captured by something much more harmful, Nikaidou, later within the episode.
Anything involving El/Eru.
Anytime Utau sees Ikuto. Expect jumping, hugging, whining, kissing and overly sweet behavior that some characters consider disturbing. Especially when Utau de-transforms in the middle of the fight just to scream "Ikuuuuutoooo!" and hug him.
Shugo Chara! Party Episode 7. Minus the purification of the X-Egg..the ENTIRE episode where 'Nadeshiko' returns.
It turns out that a poster of Nadeshiko's performance was earlier release and Nagihiko, Amu and Rima just realize it.
Kusu KusuNearly reveal Nadeshiko's identity but was saved thanks to Dia.