Fast Times at Ridgemont High(1982)
On the surface this film is what it is, a classic story of the teenagers quest for sex and parties. But what might surprise you is the ways in which this film takes it's shares of serious terms. A girl must face the trials of pregnancy andf abortion, a young man realizes that his long time friend is in fact a loser who shirks responsibilities, especially fatherhood. Like many films, this is a fun coming of age tale with dramatic results. Oh yeah, and then there is Phoebe Cates topless.
This is the theatrical trailer without watermarks, but with the MPAA band and credits.