There is an opening sequence where two drug dealers jump out of a plane. They are both speaking Spanish, but the subtitles are in Korean (which obviously, IS the joke!). According to the DVD commentary, the dialogue translates to: First man - "Oh my God, we're going to die!", Second man - "Did I remember to close the garage door this morning?"
The song that Peter sings to get the students to quit the drug, "Give up the toad now," is, obviously, a reference to "You're the one that I want" from the movie Grease (1978).
The girl in the sequence in the schoolhouse actually recited the quadratic formula for the teacher.
Towards the end of the episode Peter is walking across the field and puts his fist in the air to the song Don't You (Forget About Me) which is, obviously, a reference to the ending of the movie The Breakfast Club.
The title is a line from the 1957 song "At the Hop" sung by "Danny and the Juniors" which reached number one on the Billboard Chart in 1958.