Mean Girls

Mean Girls is a 2004 American teen comedy movie starring Lindsay Lohan, Rachel McAdams, Tim Meadows, Ana Gasteyer, Amy Poehler, and Tina Fey. It was written by Fey and directed by Mark Waters.
Plot.
"Mean Girls" is about a teenage girl, Cady Heron, who used to be home schooled in Africa but moves to the United States and has to go to a normal high school in Evanston, Illinois. On her first day at school, she hates it. She thinks it is a bit weird because she cannot go to the toilet when she wants, cannot write in green ink and has to stay in the same seat every time she goes into a lesson. On the second day it becomes more successful as she makes new friends, Janis and Damian. When they skip a lesson, Janis and Damian give her a map of the school eating area. It is arranged into different sorts of people and their personalities. At lunch time Cady is on her way to sit with her new friends but is interrupted, then Regina, Gretchen and Karen ("The Plastics") ask her to sit with them and so she sits with them.
Soon, Cady joins the Plastics, and Janis devises a plan to shatter them. Cady convinces Regina to eat these bars that will make her gain weight instead of lose weight.
However, Cady becomes too much like the Plastics, and throws a party at her parents' house without their permission. She tries to hook up with Regina's boyfriend, but he rejects her because she's "just like a clone of Regina now". Janis tells Cady that she's just like one of the Plastics now. Low grades in calculus class force Cady to rethink her plans. She joins the math team, and works on getting her grades up. She manages to help the math team win a championship.
Sequel.
"Mean Girls 2" was released in 2011 on DVD. None of the actors from "Mean Girls" were in it apart from Tim Meadows.