Left Behind: The Kids, books 29 & 30, by Jerry B. Jenkins, Tim LaHaye, and Chris Fabry. Paperbacks.
As I have written here before, I am a completist, and when I finished the Left Behind series a number of years ago, I started working my through the Kids versions of the books.And once started, I don't want to finish. I read them two at a time, two or three times per year. Maybe some time in 2015 I'll be done.
As I have written before, there is a level of impressive work here, in being able to tie in this series to the greater "adult" stories, where events and plot has to coincide.