Mean Girls is a 2004 American teen comedy film directed by Mark Waters. The screenplay was written by Tina Fey and is based in part on the non-fiction book Queen Bees and Wannabes by Rosalind Wiseman, which describes how female high school social cliques operate and the effect they can have on girls.
Mean Girls Trailer - I never really liked this film, though it's probably because I can't relate to the phoniness of it all. But it is a modern take on teenagers today, using all the proppian characters and plot twists than nearly all films use. I'm not sure if it's a classic, but it's intelligently made.