John Kapelos plays the teacher in this episode, the one that gives them this assignment to find out who the other person is. He gives them labels, and is referred to as "Carl" in the episode. John Kapelos also played Carl, the janitor in The Breakfast Club (1985), which most of this episode seems to reference.
In the scene where Bevin and Rachel are in the boys bathroom, the guy standing next to Bevin is Hilarie Burton (Peyton)'s younger brother Billy.
Haley does an impression of Joey Potter from Dawson's Creek. Dawson's Creek and One Tree Hill were both filmed in Wilmington, North Carolina and both Chad Michael Murray(Lucas) and Hilarie Burton(Peyton) starred in Dawson's Creek.