The end of the episode references the way Saturday Night Live ends each one of their episodes
In the opening credits and the individual scene transitions, the lettering over the campus archway has been changed from "Hollywood Arts High School" to "Hollyweird Arts Pie School" likely put there as an April Fools prank.
During the opening credits, when Tori opens the doors to the school, a bubble appears and flies across the screen. In the bubble you can see a picture of the cast of iCarly, another show created by Dan Schneider.
Ariana Grande as Cat plays Dorothy in the Wizard of Oz sketch. Ariana goes on to play Glinda in the Wicked films.