Trivia: For his role, Kiefer Sutherland had to practice roaring like a lion. Instead of doing it at home with his daughter and step-daughter around, he practiced in his car, unaware of a woman watching him from the next lane.
Trivia: The boat that takes George to America, and again back to Africa, is named the H A Rey. This is a tribute to the author of the Curious George children's books.
Trivia: Maya Rudolph, who plays the pregnant character Molly, was actually pregnant during the filming of the movie.
Trivia: The movie which the girl and the baby are watching just before Grant visits them is "The Toxic Avenger" a popular Troma Release.
Trivia: In the epilogue, all of the characters' fates are accounted for, except for the fact that Noah Dietrich's account of Howard Hughes' life, which formed the "rough draft" of Clifford Irving's hoax, WAS published (presumably after considerable editing) as a mass-market paperback after the scandal struck.
Trivia: Abigail Breslin, who plays Trish the elf girl, is the younger sister of Spencer Breslin, who plays Curtis.
Trivia: Actress Amy Adams makes a small cameo during the "Master Exploder" sequence. She is the woman who mouths "I love you!" to Jack Black, and is subsequently covered with the brains of the man whose head explodes.
Trivia: The four customers who are seated behind Sheryl and Richard during the diner scene are the parents of the movie's directors Jonathan Dayton and Valerie Faris.
Trivia: Marilyn Dean tells Brooke (Jennifer Aniston) to go see her personal waxer at the spa and to ask for the "Telly Savalas". Telly Savalas was Jennifer Aniston's godfather. (00:56:00)
Trivia: Included in the film's soundtrack are the songs from performers/composers who have themselves committed suicide, such as Joe Meek and Rozz Williams.
Trivia: Catherine Tate plays James McAvoy's mother in the movie, even though in real life she's only 11 years older than him.
Trivia: There are many places to see references to the show The Dukes of Hazzard in this movie. For one, when Danny is playing Hold 'Em with her friends, her hat is a General Lee hat and the box they put their money in is a Dukes of Hazzard lunch box. Another is that when Danny is talking her mom into money, on the fridge there is the famous picture taken of the very first jump made by the General Lee.
Trivia: Kane Hodder, famous for playing Jason Voorhees in the majority of the Friday the 13th series makes a cameo near the beginning of the film as a man outside his house refusing to answer questions from the interviewer.
Trivia: Jane Lynch plays Lucy Bobby, the mother of Ricky Bobby (Will Ferrell). In real life, Lynch is only seven years older than Ferrell.
Trivia: When one of the men is pulled down by a sheep whilst trying to get into a car during the sheep attack on Angus' speech, he yells the Wilhelm scream.