The foul-mouthed band playing at the wedding is a real rock band called The Dan Band. They have also appeared in _Starksy & Hutch (2004)_ and The Hangover.
Vince Vaughn signed his contract for the movie during the scene with the wedding. It was his first day of shooting and he had to sign the contract before he could start.
During the KY Jelly wrestling scene the two female wrestlers are announced as residents of Hayden Hall. In reality, Hayden Hall is a dorm at director Todd Phillips's alma mater, New York University.
Breckin Meyer has an uncredited role as a Highway Officer in the deleted scenes available on the DVD. Meyer previously starred in Road Trip, also directed by Todd Phillips.
The Writer, Court Crandall, an alumni of University of New Hampshire ('87), based the story on his experiences at Phi Kappa Theta fraternity and his role as a husband and father of two boys.
The song "Here I Go Again" by Whitesnake is played four times in the movie - twice with the words, once without, and once hummed. The band Whitesnake is also mentioned by Mitch when he references Nicole's high school jean-jacket. Frank also wears a Whitesnake t-shirt at the very end of the movie, during the credits.