While you're waiting in line to see The Dark Knight, here's something to occupy your mind: Adrien Brody was considered to play the Joker; Matt Damon turned down the part of Harvey Dent and, if Katie Holmes had elected to reprise her role from Batman Begins, there would be no Maggie Gyllenhaal. Nothing brings the power of casting into focus quite like imagining the new Batman movie with different actors, especially without Heath Ledger. "These decisions to take roles or not can drastically alter an actor's career path or a film's place in history," explains Mike Clem, founder of notstarring.com; a site about actors and the roles they didn't get.

Clem started the website in 2002 because, although this trivia existed, it was scattered all over the place. Clem thought it would be a good idea to "pull it together into a single archive that could be searched by both film or actor." Given the amount of traffic the site now gets ("thousands of visits a day from over 190 countries"), it seems he was right. But it's more than just the fact that the information is well organized and in one place -- there is something addictive about reading an entry and thinking, "what if?" The Fan Favorites section highlights the entries that are the most popular. Did you know that John Denver turned down the lead in An Officer and a Gentleman? That Will Smith opted not to play Neo in The Matrix? Here's one for those that like the classics: Zefferelli wanted Paul McCartney to be his Romeo. "The most interesting trivia is when the actor openly shares their reasons or regrets about not taking a role," says Clem. In the case of McCartney, he turned down a chance to star in the famous 1968 version of Romeo and Juliet because he didn't think he was a good enough actor to take on Shakespeare.

Movie trivia fans don't just benefit from the site, they help build it. "We are blessed with a fantastic group of volunteers who help maintain the site," explains Clem. "Over 1200 different people have actively contributed content." The volunteers also help keep it honest. "We receive far more entries than what we post to the site," he notes and if there's a mistake, "We have a great group of regulars who are quick to correct us when confusing or inaccurate trivia slips through."

Will they add other trivia in the future? "Notstarring.com has always focused on roles that were turned down in feature films, but we are often asked if we have similar trivia for television," says Clem. If you're wondering, say, who else auditioned for the role of Don Draper in Mad Men, Clem might be able to help. "We have amassed a great deal of TV trivia, so that is something we hope to roll out soon." Meanwhile, he enjoys seeing the community that has developed around the site, "It's cool to see how a fun little site can be so contagious," he says. "So please go tell 100 of your friends!"