Roger Rabbit
3. Ever wondered exactly how many cartoon cameos there are in the film?
At the time, the film was perhaps best known for collecting a whole host of cartoon cameos, and it marked the first time that Warner Bros. and Disney characters had appeared on screen together. The negotiations -- which Spielberg was instrumental in -- were tricky, but a flat fee of about $5000 per character was agreed on, with some other regulations here and there. For instance, Warners execs only agreed to release Bugs Bunny and Daffy Duck if they had the same amount of screen time as Disney's icons, which is why Daffy is paired with Donald Duck, and Bugs with Mickey. 

The Disney characters that cameo are: Mickey & Minnie Mouse, Pluto, Donald Duck, Goofy, Pegleg Pete, Horace Horsecollar, Clarabell Cow, The Merry Dwarves, Huey, Dewey & Louie, Clara Cluck, Gus Goose, Bucky Bug, "The Water Babies," "Cock o'the Walk," Elmer Elephant, Joe Giraffe, Willie The Giant,  the title characters from "Flowers and Trees" and "Three Little Pigs" (with the Big Bad Wolf also featuring from the latter), Peter Pig, Toby Tortoise, Max Hare (along with the female bunnies from "The Tortoise and the Hare," the orphans from "Orphan's Benefits," Little Red Riding Hood, Jenny Wren, Elmer Elephant, Snow White, the witch and the Seven Dwarves from "Snow White and the Seven Dwarves," the title characters from "Wynken, Blynken and Nod," Ferdinand the Bull, Pinocchio, Jiminy Cricket, Lampwick, various characters from "Fantasia" (the broomsticks, the cupids, the Pegasi, an ostrich and the hippo, "The Reluctant Dragon," plus Sir Giles, "Dumbo" along with Mrs. Jumbo, Casey Jr and the crows, "Bambi," "Chicken Little," Jose from "Saludos Amigos," the pelican from "The Pelican and the Snipe," Peter from "Peter and the Wolf" in "Make Mine Music," Br'er Bear, the groundhogs and the tar baby from "Song of the South," the singing harp from "Fun & Fancy Free," animals from "Johnny Appleseed," Danny the lamb from "So Dear To My Heart," Mr. Toad & Cyril, Tinker-Bell, Maleficent's henchmen from "Sleeping Beauty," Mr. Walker from "Motor Mania," Alice from "Alice In Wonderland," plus Bill The Lizard, Tweedledum, The Cheshire Cat and the doorknob, the mother from "Lambert The Sheepish Lion," the buildings from "The Little House," Witch Hazel from "Trick or Treat," Kaa and a vulture from "The Jungle Book," Piglet from "Winnie The Pooh" and the penguins from "Mary Poppins." 

Meanwhile, Warner Bros contributed: Bugs Bunny, Daffy Duck, Porky Pig, Sylvester & Tweetie, Yosemite Sam, Foghorn Leghorn, Marvin the Martian, Road Runner & Wile E.Coyote, the bulldog from "Feed The Kitty," the sheepdog from "Don't Give Up The Sheep," Yoyo Dodo, Gracie the kangaroo, Toro the bull and Speedy Gonzalez. Others included: Koko The Clown, Wiffle Piffle, the Noveltoons logo and Betty Boop (Fleischer), Woody Woodpecker, Wally Walrus and Papa Panda (from Walter Lantz), Gandy Goose (20th Century Fox), Felix The Cat (King) Lena Hyena from "Li'l Abner" and Droopy, Spike, Screwy Squirrel, Meathead, Benny Burro, Barney Bear, George and the octopus for "Half-Pint Pygmy" (MGM). Those that the film wasn't able to strike a deal on include Fleischer's Superman, Popeye, Tom & Jerry, Little Lulu, Casper the Friendly Ghost, and most of the Terrytoons characters.

Roger Rabbit
4. Earlier drafts had Jessica Rabbit as the villain, and at one point, Judge Doom was the killer of Bambi's mother
Given that it was in various stages of development for over a decade, it's not surprising that the script went through many, many iterations over the years, with the biggest changes occurring when it came to the villain. Early drafts saw Jessica Rabbit, and even Baby Herman, as the answer to the question of the title "Who Framed Roger Rabbit," but eventually Price & Seaman created Judge Doom, the sinister, pale fascist who turns out to be a toon in disguise. The writers were inspired by "Chinatown" for Doom's master plot, but the character still went through a number of different iterations. Until quite late on, he was meant to have an animated vulture sitting on his shoulder, while he carried a suitcase containing 12 kangaroos, which served as a jury (their roos would produce letters from the pouch, spelling out Y-O-U A-R-E G-U-I-L-T-Y). Somewhat sensibly, both ideas were dropped, as was one of the more interesting concepts. Another script draft filled in Doom's backstory as the hunter who killed Bambi's mother (it was ultimately vetoed by Disney). His weasel henchmen were also a homage to classic Disney, modeled as a twisted parody of the Seven Dwarves, named Stupid, Smart Ass, Greasy, Wheezy and Psycho (Slimey and Flasher were left on the cutting room floor, rather ruining the symmetry). Finally, Christopher Lee is said to have been the first choice for the part, before "Back To The Future" alumnus Christopher Lloyd reunited with Zemeckis instead.

Roger Rabbit
5. A World War II-set prequel was planned, but never quite got made
Over the years, Roger Rabbit has popped up in a various places, but despite the original being a critical and commercial hit, the character's yet to star in a feature sequel. There were comic books that continued the story (most notably "Roger Rabbit: The Resurrection Of Doom"), and the character and various others headlined three theatrical shorts in the years after the film was released. The first, "Tummy Trouble," premiered a year after "Who Framed Roger Rabbit," in front of "Honey I Shrunk The Kids," with "Roller Coaster Rabbit" following in 1990 with "Dick Tracy," and "Trail Mix-Up" proving the last, in front of "A Far Off Place" in 1993 (a fourth, "Hare In My Soup," was planned, but Steven Spielberg, who part-owns the character, put the kibosh on it after Disney attached the second short to "Dick Tracy" rather than the Spielberg-produced "Arachnophobia"). While these were being made, there was also a full-on theatrical sequel in development. 

Penned by "Dr. Doolittle" and "Open Season" writer Nat Maudlin, "Roger Rabbit: The Toon Patrol" was set before the original film, and started with Roger's early life on a farm in the Midwest, before he sets out to find his parents, joining the army and meeting his future wife Jessica, who he has to rescue from the Nazis, ending with Roger discovering that his father is really Bugs Bunny. Later in development, it was retitled "Who Discovered Roger Rabbit," and was retooled to follow Roger's rise to stardom on Broadway, but Spielberg got cold feet after making "Schindler's List" and vowing not use Nazis as villains in escapist fare from then on. "Casper" writers Sherri Stoner and Deanna Oliver were brought on to rewrite, and Disney vet Alan Menken was even hired to write some songs, but the film mostly languished in development hell. In the late 1990s, some tests were performed, with the toons now CGI creations, but Disney cancelled the project. In recent years, original writers Jeffrey Price and Peter S. Seaman have been working on a brand new script, but Zemeckis told us recently it's not something he sees happening any time soon, saying: "I'm not planning any sequel. All I know is there's a draft for a sequel sitting at Disney. It's good, but I don't know what's going on, it's just a great script sitting."