The Incredible Hulk - When Mr. Turner sleep-drives, he pass by a purple look-alike version of Hulk. This also refrences The infragable Klunk, because of his color
When Mr. Turner lands his car in Adrenaland, it is parked in the center of the amusement park. At the end of the episode, the car is parked in the parking lot.
Cosmo and Wanda turn Timmy into sixteen year old Gah in the middle of the park earlier with no problem, but when he wants to be wished back, Cosmo and Wanda cannot use their magic because they are in public. However, this is probably because no one was paying attention to Timmy earlier, but when he was Gah, people were following him around like a supermodel since they thought he was one.
Though Timmy called it Norwegia, Norwegians actually come from Norway.
Characters saying "that's the password" and dropping somebody down a trapdoor.
When Gah says "help", Vicky thinks that it means "I love you" in Norwegian.