The scenes featured in the film where Jack Black and Ben Stiller are in Rome were actually shot in Rio de Janeiro, Brazil, due to the fact that the film was already over-budget and shooting in Italy would have been significantly more expensive.
Writer Steve Adams is the Nephew of novelist Kurt Vonnegut. Bosco's line "Up your ass with Mobil gas" is taken from Vonnegut's book Breakfast of Champions.
The movie having been shot almost two years before it was released in theaters was in danger of being released straight to video due to poor audience response during test screenings. It was only due to School of Rock (2003)'s huge success that it finally got a theatrical release.
When Tim goes to Nick's house after J-man answers the phone, Tim knocks on Nick's door, and when their butler opens the door, the door and the frame wobble back and forth for 2 or 3 seconds.