
Trivia: The entire "How am I funny?" scene was improvised by Joe Pesci and Ray Liotta.
Suggested correction: False. Joe Pesci told the anecdote to Scorsese in the earliest stages of the movie. Scorsese asked him to add it during previous script readings and further rehearsals while notes were being taken by crew members. Then it was finally shot following those rehearsals and notes. In this video all the actors involved tell how Scorsese works and even he himself says he rewrote that scene 4 times. Minute 13:04: https://youtu.be/_bbzUZuxEB8.
I have actually seen interviews where they admitted it was improvised. The reactions from the other actors was genuine.

Trivia: The hat band on John Wayne's hat once belonged to Gary Cooper. It was a gift to John from Cooper.

Trivia: Richard Gere actually plays the piano - and he composed this piece himself.

Trivia: When James Brolin was offered the role of George Lutz, he was informed that they didn't have a script to give him. James bought a copy of the novel and began to read it. At two o'clock in the morning, while reading a very intense part of the book, a pair of pants that he had hung up earlier fell to the ground causing him to jump in fright. After that, James agreed to do the film.

Trivia: Director Tyler Perry loves his cast so much that most of them are in all of his films. Besides changing up the main characters, he always finds a spot for his regulars.

Trivia: Charlie Sheen stayed awake for 2 days to play the guy in the police station, so he could get the right look for the scene.

Trivia: At the climax of the movie when Russell Crowe confronts Senator Collins about his involvement with the death of the senate research aid, he goes outside to leave and is accosted by the assassin, Robert Bingham. Bingham is apparently going to kill Crowe when the police show up in force. Bingham raises his M-16 to shoot Crowe and the police shoot him. In the next scene Crowe is entering the news article in the newspaper's computer. The camera gives us a glimpse of the computer screen. If you pause it and read the story it says that the assassin, Bingham, is found by the police dead at his apartment from an apparent suicide instead of being shot down in a fusillade of police gunfire in front of Senator Collins' office.

Trivia: Yvonne Elliman and Barry Dennen, as Mary Magdalene and Pontius Pilate, respectively, are the only cast members who appeared on the concept album, in the original staging of the show on Broadway, and in the feature film.

Trivia: Linda Harrison, who portrayed Nova in the original Planet of the Apes and its sequel Beneath the Planet of the Apes, has a cameo appearance in this movie as one of the people inside the rolling cage as it's being taken into the city. She is seen standing next to Mark Wahlberg, shaking her head when he asks her a question.

Trivia: Director Jason Reitman is the son of Ivan Reitman, director of the original "Ghostbusters" and "Ghostbusters II." As a child, Jason actually had a cameo in "Ghostbusters II" during the birthday party in the beginning. (He's the kid who tells Ray he heard the Ghostbusters were "full of crap").

Trivia: Kathleen Marshall, who plays the role of Charlotte, is the director Garry Marshall's daughter.

Trivia: Satan is actually played by a woman - the Italian actress Rosalinda Celentano.

Trivia: The name of Truman's boat is the "Santa Maria" - a ship sailed by Christopher Columbus. It is symbolic of going to a new land or a "new" place.

Trivia: When Donnie is about to enter the car with Gretchen near the end of the film, he clutches at his stomach as if in pain, and we see Frank touch his eye after Donnie dies. Both these moments foreshadow pain: a deleted scene of Donnie's death shows a pole impaling his stomach right where he clutched it. And Donnie shoots Frank in the eye.

Trivia: The Noordermarkt scene in Amsterdam was not really shot there. In fact it wasn't shot in the Netherlands at all. The Noordermarkt in the film looks nothing like the real Noordermarkt, and more like an Asian or Indian market. The noise of people talking in the background does not resemble anything close to Dutch. The cars in the scene are rarely seen in the Netherland because they are too outdated to be seen frequently, especially all together. At timecode 42:30 you can see a police car with "POLICE" written on the side of it. However, in real life, Dutch police cars do not use the English word for police. "Politie" would have been the correct word, but even then the police car would not be convincing, as official police cars look entirely different. Finally, the firetruck appearing later in the scene is not a type used in the Netherlands, but appears to be an American Pierce Lance truck with Dutch fire engine stickers on it. Dutch firetrucks are usually of European make: DAF, MAN or Mercedes. (00:41:50 - 00:43:30)