At twelve years old my favorite book was The Hobbit. I have not reread it since that age but I remember it being exciting to read such a large, adult seeming book at the time. If you have any kids looking for a longer summer read that enjoy fantasy stories try Tolkien on for size. This is especially recommendable for kids that have already read series such as Harry Potter, Pendragon, or The Chronicles of Narnia but want to move on to something more challenging. Plus after finishing the book they can look forward to watching the awesome animated movie based on the story, which the library also carries.