Wouldn't it be great if you could warn your younger self against some of the really dumb choices you've made? In Gimme a Call, by Sarah Mlynowski, one girl gets that chance.
When high school senior Devi Banks drops her phone in the fountain at the mall, suddenly she finds that it will only call to one number--her freshman self. The first thing she does is to warn Younger Devi not to date Bryan, the boy who's just cruelly broken Older Devi's heart. She follows that up with all the things she wishes she'd done so she won't end up where she is--friendless, loveless, and about to go to a really bad college.
But Younger Devi doesn't understand why she has to study harder, join a million clubs, give weird advice to her friends, and most of all, ignore sweet and cool Bryan who really seems to like her. As she follows a torrent of confusing advice from her older self, both girls find their lives changing around them. But are these lives the ones they really want?
Funny and a little brain-bending, this is a book for anybody who's ever believed that teenagers don't have regrets, and anybody who knows differently.