Jim Downey as Principal/Judge of the "Decathlon" in BILLY MADISON (1995). Downey was a long time writer for NBC's SATURDAY NIGHT LIVE. He worked on 27 of the show's first 32 seasons, one of the longest tenures in the show's history. © Universal Pictures

Screenplay writer David Koepp just before getting eaten by a T-Rex in THE LOST WORLD: JURASSIC PARK (1997). © Universal Pictures

Author John Irving is the St. Cloud, Maine Stationmaster in THE CIDER HOUSE RULES (1999). Based on his novel of the same name, he won the Best Adapted Screenplay Academy Award. © Miramax Films

In the Martin Scorsese directed BRINGING OUT THE DEAD (1999) , the emergency room patient in the brown jacket is Joe Connolly, the author of the book of the same name. © Paramount Pictures

The 1999 film JESUS' SON, based on the Denis Johnson book of the same name has Johnson himself showing up at a hospital with a big knife buried to the hilt in his eye socket. Hospital attendant Jack Black brings Johnson in, adding that he had nothing to do with this injury. © Lionsgate

EVIL DEAD II co-writer Scott Spiegel appears as a man who attempts to eat some pizza Spider-Man is delivering in SPIDERMAN 2 (2004). Spiegel and SPIDERMAN director Sam Raimi were also High School classmates and longtime friends. @Columbia Pictures

In HOT FUZZ (2007), THE OFFICE (UK) co-creator/co-writer Stephen Merchant shows up as Peter Ian Staker. He calls the Sanford police office to report the town swan as missing and provides a description ("...about two foot tall, white, a bit of black across the head... well, he's a SWAN.") © Universal Pictures

THEN SHE FOUND ME (2007) is the directorial debut of Helen Hunt. Coming in a few times throughout the film is author Salman Rushdie as Dr. Masani, Hunt's OBGYN. © ThinkFilm

Oscar-winning screenwriter Aaron Sorkin plays an ad executive with a napping Jesse Eisenberg and Andrew Garfield in THE SOCIAL NETWORK (2010). © Columbia Pictures

Co-screenwriter Annie Mumolo (along with co-writer Kristen Wiig) as a nervous passenger in BRIDESMAIDS (2011). © Universal Pictures

J. Michael Straczynski, one of the two writers of THOR (2011) discovers a strange sledge hammer imbedded in the New Mexico desert. Straczynski is probably best known as the creator of the Sci-Fi series BABYLON 5. © Marvel Entertainment

Brian Selznick as an uncredited Eager Student in HUGO (2011). Selznick wrote the children's book, "The Invention of Hugo Cabret" whuch follows a young orphan in Paris in the 1930s as he tries to piece together a broken automaton. The book was inspired by a passage in the book Edison’s Eve by Gaby Wood that tells of the collection of automata that belonged to Georges Méliès. After his death they were thrown away by the museum that he donated them to. Selznick, a fan of Méliès and automata envisioned a young boy stealing an automaton from the garbage © Paramount Pictures

TINKER, TAILOR, SOLDIER, SPY was a 1974 spy novel by British author John le Carré, which was made into a critically acclaimed film in 2011 starring Gary Oldman. John le Carré appears in a cameo as a guest in a party scene, standing on the right. © StudioCanal

THE ADVENTURES OF TINTIN (2011) is an animated film based on a series of comics by Belgian writer & artist Georges Prosper Remi, also known as Hergé. As a tribute to the writer/artist, who passed away in 1983, director Steven Spielberg & co-producer Peter Jackson had him make a "cameo" in the opening shots as a street artist sketching a portrait of the films Tintin in the same style as his classic comics. © Paramount Pictures

Adapted from his 2004 novel, David Mitchell makes a very brief uncredited cameo in CLOUD ATLAS (2012). © Warner Bros.