1. Lindsay Lohan's original role was Regina, but was switched to Cady so moviegoers wouldn't associate Regina's negative attitude with Lohan's.
2. And Amanda Seyfried originally had the role of Cady.
3. You might recognize Gretchen Weiner's voice from somewhere else - Lacey Chabert did the voice of Eliza Thornberry.
She was also the voice of Meg on "Family Guy" before Mila Kunis took over.
4. In an alternate universe, Ashley Tisdale plays Karen Smith.
5. Scarlett Johansson also almost played Karen.
6. At the time of filming, Rachel McAdams was eight years older than Lindsay Lohan, her classmate, and seven years younger than Amy Poehler, her mother.
7. Tim Meadows' character's carpel tunnel was added to the film because Meadows broke his hand before shooting.
8. Also, during the above scene, Tim Meadows' character says, “I did not leave the South Side for this!” This is actually a quote from another movie called Lean on Me, which is "about a principal struggling to improve a decaying school."
9. Rachel McAdams’ hair was a wig.
10. GLENN COCO IS AN ACTUAL PERSON! He's David Reale, a Canadian actor born 1984. For some horrible, horrible reason this role was not credited in the movie.
AND HE'S ON TWITTER!
11. This is what the business card that Kevin G. gives Cady actually says:
12. The movie's original script had Cady being asked if her cherry was popped instead of if her muffin was buttered.
13. The song Cady "actually recognizes" at the school dance is called "Built This Way" by Samantha Ronson. Lindsay Lohan would go on to date Ronson a few years after the movie's release.
14. Yeah, there's a Mean Girls video game.
15. The Plastics wear skirts made out of plastic for the winter talent show in order to “represent the Plastics.”
16. Mean Girls is based on the book Queen Bees and Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends, and Other Realities of Adolescence by Rosalind Wiseman.
17. Janis Ian, Lizzy Caplan's character, is named after Janis Ian, the first Saturday Night Live musical guest.
18. Lindsay Lohan's character is named after Elizabeth Cady Stanton of the American Women's Rights Movement.
19. When casting the film, Tina Fey picked the actor who plays Aaron Samuels because she thought "he looked like Jimmy Fallon."
This is what he looks like nowadays:
And he's on Twitter:
20. While we're at it, here's Kevin G. then...
And this is what Kevin G. is looking like nowadays:
Also, not too long ago, Tina Fey, Amy Poehler, and Kevin G. got together to reenact his infamous rap.
View this video on YouTube
21. And Shane Oman? He's MIKE ON HOMELAND!
22. And, finally, this is what all the girls look like now:
This post has been updated to meet our attribution standards.