Denise Richards claims that her derriere was digitally enlarged for the film's cover and promotional material.
Gary Anthony Williams ("Smart Brother") originally provided the voice of Undercover Brother on the Internet animated series (on which this film is based).
Ironically, while the movie's protagonists are African-American and the opening credits track African-Americans in the mainstream pop culture through the 1960s, 1970s, 1980s and 1990s, the movie opens with "Pick Up The Pieces". The song, while a pop funk classic, was performed by the Average White Band, a group of Caucasian Scotsman whose music and soulful singing style were heavily influenced by African-American funk and soul.
In the scene where Lance emerges from the van in a cloud of pot smoke, Neil Patrick Harris thought it would help his performance to get stoned for real prior to filming. Harris claims this ended up backfiring by making him sluggish and paranoid.
The building used as the Island Fortress is actually a water filtration plant in the Beaches area of Toronto. It has been the scene of other movies, including the mental institution in In the Mouth of Madness (1994). Filming can no longer take place inside this building following the terrorist attacks on the USA of 11 September 2001.