The party: An almost end of school party where our protagonists attempt to buy booze and chat up the girls they have crushes on. This is one of my all time favorite comedies. A lot of the kids in this film reminded me of a few I went to high school with.
2) American Pie
The party: An after prom party where our main boys all want to lose their virginity. I always call American Pie "my" high school movie even though it came out when I was in junior high. It was one that everyone saw, but never told our parents we watched it. It still holds up.
3) This Is The End
The party: James Franco throwing one because fuck you that's why. I love this movie. You have to love it when actors don't take themselves too seriously.