Heathers

1989 dark comedy directed by Michael Lehmann and starring Winona Ryder and Christian Slater.

High school girl takes up with the school's rebel to rid the school of a clique of uber-popular girls. Outrageous and certainly different.

Slater's performance stands out as he channels Jack Nicholson. Winona Ryder shines.

http://www.imdb.com/title/tt0097493/