I can't really answer this question, or shouldn't I should say, as I am still a teenager at nineteen. I must say that the best thing about being a teenager so far is all the friends. They may be people you only talk to while in high school, but there are a lot of them. Once you leave high school, chances are you'll never speak to them again.
The hang-out for the group I stuck around with in high school was the library. A lot of us read books, yeah, but even those who didn't found it kind of cool for two reasons: one, the librarian was a young woman who actually joined most of the conversations, and two, it was quiet and we had the place to ourselves (mostly).