Joaquin Phoenix claims to have seen this film more times than he has seen any other movie. He later starred with John C. Reilly in The Sisters Brothers.
When Brennan and Dale are in their room, showing each other their night vision goggles and autographed sword, the camera pans around while the characters are walking, and a Hugalo's Pizza car light is on top of the chest of drawers in the room. Will Ferrell's character worked for Hugalo's Pizza in Talladega Nights: The Ballad of Ricky Bobby (2006), after he lost his job as a race car driver.
In the commentary, Adam McKay said that they originally went to Catalina Island for location shots, and discovered that he didn't really like it. Instead, they shot on the coast. Catalina Island appears in several shots, and McKay chose not to have it digitally edited out, as a joke.
Mary Steenburgen played Will Ferrell's stepmother in Elf (2003). In this film, Steenburgen plays Ferrell's mother.