When filling in the multiple choice answer paper, Randy (Ethan Suplee) holds up his sheet saying "...it's a sail boat". This is a reference to his character in Mallrats who, throughout the entirety of the film, fails to see a sail boat within a magic eye picture.
One of Earls old teachers he goes to to help him with the G.E.D was named Mr. Baldwin. In real life Jason Lee is a descendant of an English Baldwin family.