At the end, Mark takes Happy Peppy Gary and Betty back to his home world, in a Smack-A-Mole game, so it would seem obvious that by School's Out: The Musical! he has FINALLY mastered it, but it doesn't show up.
The "Get Ready For This" sound-alike that played in the arena was later used in the ChalkZone episode "Lost in ChalkZone". This is the second time a music cue from The Fairly OddParents was re-used in ChalkZone, the first time being the first music cue in "The Fairly OddParents! (episode)" being played in "Future Zone". Like The Fairly OddParents, ChalkZone also initially started out as a series of shorts on Oh Yeah! Cartoons and shares a number of staff members with The Fairly OddParents. Guy Moon composed both shows.
Vicky - "Help me, Mark Chang! You're my only hope!" - When Cosmo sends Mark Chang the fake message and Vicky says this, it is a parody of Star Wars: A New Hope, where Princess Leia's message says "Help me, Obi-Wan Kenobi. You're my only hope!".
When Mark wants to fight with Timmy, he calls it "Dijifat" but he then says that he sneezed and it's called "Death Combat", but then when he surrenders he calls it "Dijifat" again.
When Mark first bumps into Pink the Polar Bear, and all we see is his leg, it resembles a realistic furry polar bear's leg. But in the next shot when we see Pink in full view, he is merely a white teddy bear.
When the kids chant, "You have a funny head!", their lips move only the first time they say it.