Stuck in the 70's — D.L. Garfinkle

One night in 1978, Tyler Gray wakes up to find a beautiful girl named Shay lying in his bathtub. For inexperienced, nerdy Tyler, this is not a common occurrence, but it's even stranger because Shay insists that she's from 2006. Of course Tyler doesn't believe her, but once she proves it, they strike a deal: Tyler will try to help get Shay back to 2006 if Shay helps him become more popular.

But the more time Shay spends in 1978, the more she likes it. And while she helps Tyler with the popular crowd, she also wreaks havoc by going out with his worst enemy, making over his sister and helping his mother get a job as a cafeteria worker--at his school! Can Tyler get Shay home before his life is completely turned upside down?