'Mean Girls' (2004)
Teenagers can be so mean...and teenage girls, especially the popular ones, can be downright vicious. Loosely based on Rosalind Wiseman's 2002 study of high school cliques titled Queen Bees and Wannabes, this female comedy fashioned itself as a kinder, gentler Heathers, albeit still with plenty of bite. Having fallen in with the "Plastics," new girl on campus Lindsay Lohan soon finds herself adopting to the intergroup hive mindset; the real humor comes less from her transformation, however, than from the way these female students burn everyone around them. (That, and the sheer stupidity of Amanda Seyfried and Lacey Chabert's characters.) Tina Fey's script confirmed that she was a first-rate comic screenwriter, and she and her Mean Girls costar/SNL buddy Amy Poehler would soon front their own female comedy, 2008's Baby Mama (itself a take on the "baby" cycle of female comedies from the Eighties). This film, however, was the one where Fey & co. moved the genre forward.