Brad Pitt says he didn't want his parents to see the movie, but he couldn't convince them not to watch. They changed their minds after watching the chemical burn scene

When the Narrator hits Tyler Durden in the ear, Edward Norton actually did hit Brad Pitt in the ear. He was originally going to fake hit him, but before the scene, David Fincher pulled Norton aside and told him to hit him in the ear. After Norton hit him in the scene, you can see him smiling and laughing while Pitt is in pain

When Tyler and the Narrator are fighting and gather a crowd, no one intervenes, but instead look rather bemused.

Tyler appears in the film five times before we clearly see him on the moving walkway at the airport. In the first four appearances, he flashes on screen for a single frame 124 of a second and only when the Narrator has insomnia

Marla Singer's phone number, 555-0134, is the same as Teddy's number in Memento. It is also the same as the Hong Kong Restaurant in Harriet the Spy, Eddie Alden's in Someone Like You... and a Mental institution in an episode of Millennium.

Some of fake names used by the narrator in the self-help groups are taken from Planet of the Apes Cornelius, as well as classic roles played by Robert De Niro such as Rupert from The King of Comedy and Travis from Taxi Driver.

Edward Norton's apartment building, Pearson Towers, which he returns to at the beginning of the film to find his possessions strewn all over the sidewalk is actually Promenade Towers located at 123 South Figueroa in downtown Los Angeles.

The sex scene between Tyler and Marla was shot using the same 'bullet-time' technique used in The Matrix

Brad Pitt and Helena Bonham Carter spent three days recording orgasmic sounds for their unseen sex scenes.

To ensure that Bob's breasts and love handles hung correctly, his fat suit was filled with birdseed, so that it would 'spill' over his pants and give the impression of sagging flesh.

Prior to filming, makeup artist Julie Pearce studied UFC bouts to see what kind of makeup effects were needed for the film, as she had never done "realistic fight makeup" before

The layout of The Narrator's Edward Norton apartment was based upon an apartment which director David Fincher lived in when he first moved to LA. Fincher decided to model the location on this apartment because he claims that whilst he was living there, he always wanted to blow it up.

Tyler Durden was originally going to recite a workable recipe for home-made explosives as he does in the novel. But in the interest of public safety, the filmmakers decided to substitute fictional recipes for the real ones

Author Chuck Palahniuk has stated that he found the film to be an improvement on his novel.

Although he refused to smoke in Rounders his character played poker for cigarettes, but did not smoke, Edward Norton agreed to smoke for this film

Palahniuk told the producers from the very start that, although he fully supported the adaptation, he wasn't interested in writing the screenplay

Voted 4 in Total Film's 100 Greatest Movies Of All Time list November 2005.

Helena Bonham Carter wore platform shoes to help close up the disparity in height between her and Edward Norton and Brad Pitt.

The movie's line "The first rule of Fight Club is you do not talk about Fight Club" was 27 of "The 100 Greatest Movie Lines" by Premiere in 2007.

The typeface used for the titles and logo is named "Fight This".

Director David Fincher initially wanted to include a single frame flash of Tyler Durden Brad Pitt during the 20th Century Fox logo, but the studio's legal department wouldn't clear him to do so

During rehearsals, Brad Pitt and Edward Norton found out that they both hated the new Volkswagen Beetle with a passion, and for the scene where Tyler and The Narrator are hitting cars with baseball bats, Pitt and Norton insisted that one of the cars be a Beetle.

...When Tyler and the Narrator hit the first car with baseball bats, Tyler hits first, but the alarm is triggered only after the Narrator hits.

Three detectives in the film are named Detective Andrew, Detective Kevin, and Detective Walker. Andrew Kevin Walker was the writer of the David Fincher film Se7en also starring Brad Pitt, and did some uncredited work on this movie's script.

To prepare for their roles, Edward Norton and Brad Pitt took basic lessons in boxing, taekwondo and grappling, and also studied hours of UFC programming...

...Additionally, they both took soapmaking classes from boutique company Auntie Godmother.

When a Fight Club member sprays the priest with a hose, the camera briefly shakes. This happens because the cameraman couldn't keep himself from laughing.

Starbucks pulled their name from the coffee shop destruction scene. They didn't mind the director placing their product throughout the film, but did not want their name to be destroyed in that scene. Therefore, the gold globe crashes into a shop named Gratifico Coffee.

Edward Norton lost 17-20 pounds for this role after having to beef up tremendously for his role as a Neo-Nazi skinhead in American History X. Norton achieved this form by running, taking vitamins and just ignoring the on-set catering.

Author Chuck Palahniuk named Tyler Durden after the character of Toby Tyler in Toby Tyler, or Ten Weeks with a Circus, and a man called Durden with whom Palahniuk worked, who was fired for sexual harassment. Marla Singer was named after a young girl called Marla who used to beat up Palahniuk's sister in school.

David Fincher claimed in an interview in UK film magazine Empire, that there is a Starbucks coffee cup visible in every shot in the movie...not sure if i believe it though

The phrase, "You're the all-singing, all-dancing crap of the world" is inspired by the book "Also Sprach Zarathustra" by the German philosopher Friedrich Nietzsche.

In an infamous incident, the Friday that the film was released theatrically in the United States, Rosie O'Donnell appeared on her TV show and revealed that she had seen the film earlier in the week, and had been unable to sleep ever since. She then proceeded to give away the twist ending of the film and urged all of her viewers to avoid the movie at all costs. Edward Norton, Brad Pitt and David Fincher discuss this incident on their DVD commentary track, with Pitt calling 'O'Donnell's actions "unforgivable".

Filming lasted 138 days, with over 300 scenes shot on 200 locations and 72 sets constructed by production designer Alex McDowell.

In the short scene when Brad Pitt and Edward Norton are drunk and hitting golf balls, they really are drunk, and the golf balls are sailing directly into the side of the catering truck.

"We've all been raised on television to believe that one day we'd all be millionaires and movie gods and rock stars." Right as Tyler says "rock star," he looks specifically at Jared Leto from the band '30 Seconds to Mars'

Director David Fincher shot over 1,500 reels of film, more than three times the usual amount for a 120 minute film.