1. The Notebook New Line Cinema Yes, The Notebook is based on a Nicholas Sparks book, but the author has said that he wrote it about his wife's grandparents. Fun fact: The Bollywood film Zindagi Tere Naam is also based on Sparks' novel. 2. Girl, Interrupted Columbia Pictures This film, which follows a girl's 18-month stay at a psychiatric hospital, is actually based on a memoir of the same name by Susanna Kaysen. Fun fact: Kaysen got the name from the Vermeer painting Girl Interrupted at her Music. 3. Chicago Miramax Films The 2002 film Chicago was based on a musical from the 1970s, which was adapted from a 1926 play. That play was about the true story of a woman, Beulah Annan (whose name was changed to Roxie Hart for the films), who murdered her boyfriend. There was also a silent film adaptation of the play, released in 1927.Fun fact: The play was written by Maurine Dallas Watkins as a class assignment for Yale Drama School. 4. The Sound of Music 20th Century Fox This film was also based on a musical, which was about Maria Von Trapp's memoir, The Story of the Trapp Family Singers. The main difference in the film is that the children's father was actually kind and loving, not a rule-following maniac.Fun fact: Von Trapp didn't even want to write a memoir, but a friend practically forced her to. 5. Almost Famous DreamWorks Pictures Almost Famous is a semi-autobiographical film directed by Cameron Crowe, who was a teenage writer for Rolling Stone and toured with bands, just like the character in the film.Fun fact: Crowe was in a near-fatal plane crash while traveling with the Who. Actually I guess that isn't a ~fun~ fact at all. 6. Black Hawk Down Columbia Pictures Black Hawk Down is based on a nonfiction book of the same name by American journalist Mark Bowden.Fun fact: Satellite images and radio chatter from the real 1993 battle were used to add authenticity to the film. 7. A Beautiful Mind Universal Pictures A Beautiful Mind was inspired by the biography of Columbia professor John Forbes Nash Jr. Fun fact: Nash's other family and son born out of wedlock were added to the film for dramatic reasons, and aren't real. 8. The Terminal DreamWorks Pictures Though not 100% based on a true story, The Terminal was inspired by an Iranian refugee, Mehran Karimi Nasseri, who stayed in Charles de Gaulle airport for 18 years. He wrote a book about his experiences titled Terminal Man.Fun fact: DreamWorks paid Nasseri $250,000 to turn his story into a film. 9. A Few Good Men Columbia Pictures A Few Good Men is based on a play that was written by Aaron Sorkin. His sister was a lawyer working on the naval base in Guantanamo Bay and told him a story about some Marines who had almost killed a fellow Marine in a hazing incident gone wrong. This spawned the idea for the play.Fun fact: Sorkin's sister told him all the details over the phone while he was working as a bartender. He wrote everything down on cocktail napkins from the bar. 10. GoodFellas Warner Bros. This mob film is an adaptation of the nonfiction book Wiseguy about Henry Hill, a Mafia member who became an informant. Fun fact: The author of Wiseguy co-wrote the GoodFellas screenplay with Martin Scorsese. 11. The Blob Paramount Pictures While the alien part of this 1958 film clearly isn't based in fact, the blob itself sure is. Apparently, back in 1950, policemen in Philadelphia saw a quivering purple blob fall from the sky and land in a field. They called for backup, probably because they wanted to make sure they weren't going crazy. By the time more cops came along, the blob had evaporated without a trace. Seven years later, a producer needed to come up with the idea for a monster movie, and remembered a newspaper article about "The Blob".Fun fact: The theatre where The Blob was filmed holds Blobfest each year, and get people to recreate the "iconic" Run Out scene from the film. 12. Patch Adams Universal Pictures Patch Adams is a real guy, a doctor and comedian who uses humour to help his patients. He wrote a book, Gesundheit: Good Health is a Laughing Matter, which the film Patch Adams is loosely based on. Fun fact: Each year, the real Patch Adams organises a bunch of volunteers to travel to various places and dress up as clowns to bring humour to orphans and patients. 13. Balto Universal Pictures Balto was a real dog in the 1920s who helped save children from the diptheria epidemic by carrying serum in Alaska. Fun fact: Though he's brown in the movie, the real Balto was a black and white pure-bred Siberian husky. 14. The Pursuit of Happyness Columbia Pictures This film is based on a real guy, Chris Gardner, a homeless entrepreneur who finally came good. Fun fact: After an interview with 20/20, Gardner realised the huge Hollywood potential that his story had. 15. American Hustle Columbia Pictures This black comedy crime film is based on a real FBI operation in the 1970s, where convicted con artists helped uncover crooked politicians. Fun fact: In the film, Jennifer Lawrence's character says that microwaves zap the nutrition out of food, according to an article by Paul Brodeur. Brodeur sued Columbia Pictures because he claims he never said that. 16. Marley & Me 20th Century Fox This adorable and heartbreaking film is based on an autobiographical book of the same name by journalist John Grogan.Fun fact: The real-life Marley was in the film The Last Home Run for two minutes. 17. 21 Columbia Pictures This film tells the true story of the MIT students who used math to win big at blackjack. It's based on a book, called Bringing Down the House, which some have said is a little overdramatic when compared with the real events.Fun fact: MIT doesn't allow filming on campus, so the movie was filmed at Boston University. 18. Riding in Cars With Boys Columbia Pictures This Drew Barrymore classic was based on Beverly Donofrio's autobiography. She also served as a co-producer on the film.Fun fact: Barrymore is two years younger than Adam Garcia, who plays her son in the film. 19. Fly Away Home Columbia Pictures This unforgettable kids film is a dramatisation of the life story of Bill Lishman, who trained geese to follow him while migrating. Fun fact: Jeff Daniels and Anna Paquin play father and daughter in this movie. Nine years later they filmed a sex scene together for The Squid and the Whale. 20. 127 Hours Fox Searchlight Pictures It's easy to forget that this is a true story, because the thought of hacking off your own arm is a pretty disgusting one. The film is based on Aron Ralston's memoir, Between a Rock and a Hard Place.Fun fact: The video camera that James Franco uses in the film is the same one that Ralston used while trapped. 21. 50/50 Summit Entertainment 50/50 was written by Will Reiser, who based it on his own experiences after being diagnosed with cancer. Fun fact: Reiser worked on Da Ali G Show with Seth Rogen, who encouraged him to write the screenplay for this movie. 22. The Great Escape United Artists This film, with its insanely catchy theme music, is based on a real escape of prisoners of war from a German camp during World War II. It's modelled off the first-hand account of Australian writer Paul Brickhill, in his book The Great Escape.Fun fact: The Great Escape was the inspiration behind Chicken Run. 23. Remember the Titans Buena Vista Pictures This Denzel Washington movie is based on the true story of football coach Herman Boone. Fun fact: There's a scene where a brick is thrown through Boone's window. In real life it was a toilet, but the filmmakers didn't want to undermine the serious situation with humour.