You all know the rest. And if you don't, stop what you're doing and rent it now (the movie is finally on Netflix!). In the ten years since, it has become one of the most quoted movies of all time.
To help you celebrate a decade of wearing pink on Wednesdays, here are five things you probably didn't know about the film:
1. Lindsay Lohan originally auditioned for mean girl Regina and landed it. Meanwhile, Rachel McAdams auditioned for nice girl Cady. At 24-years-old, McAdams was told she was too old to be Cady. However, Lohan was filming "Freaky Friday" at the same time, and playing a mean girl was not going to be good for her rep (go figure). The role of Cady was given to Lohan, and McAdams was deemed perfect as Regina. (P.S. If the characters were all the same age as the actors playing them, Regina's mom - played by Amy Poehler - would have been 7 years old when her daughter was born.)
2. Rachel McAdams wasn't the only choice for Regina. Amanda Seyfried also auditioned for the lead mean girl, giving a different, yet scary spin on the character. In the end, however, it was McAdams who appeared more intimidating as Regina. The studio had Seyfried read for the "dumb girl," and now we'll never look at weather tellers the same. ("My breasts can always tell when its gonna rain" - Karen Smith.)
3. Glen Coco is a real person! The Canadian actor's name is David Reale, and his name was accidentally omitted from the credits. But his character's name will go down in infamy. "You go Glen Coco!"
4. Mean Girls in its original form would have been rated R. To give it a PG-13 rating, Paramount had to change a few lines and cut a few scenes.
5. The movie is based on the non-fiction book, "Queen Bees & Wannabees: Helping Your Daughter Survive Cliques, Boyfriends & Other Realities of Adolescence," by Rosalind Wiseman. Never has self-help become so interesting!
And there you have it. No go forth and wear pink, and leave your favorite Mean Girls quote in the comments.