What can you say about American parties ? (Что вы можете сказать об американских вечеринках?)

I've watched a lot of American movies about high school love and parties. Based on this I can say that about sixty percent of American parties are held on the roofs and they often arrange fights and showdowns.

Thus, a typical American party should be held on the roof and also does not do without the "sharp" moments of the holiday.