4th grade Sci-Fi

There is an astounding lack of material in this category. I am extremely depressed because I'd REALLY like to teach a Science Fiction novel next year (I'm trying to do one from every genre). Among the approximately ten books the librarian had on her list, there was the classic A Wrinkle in Time and a newer Newberry Award winner When you Reach Me.

I read When you Reach Me in 2 days and it was fantastic. It is a mystery that is inspired by A Wrinkle in Time but has no time travel until the very end of the book. It doesn't read like a Sci-fi novel, but is very intriguing and easy to read. I think it would be a good begining book for my fourth graders, but it kind of gives away spoilers to A Wrinkle in Time. This is tragic, because A Wrinkle in Time is one of my all time favorite books (and drips with sci-fi qualities).

So, my dear friends... I have a dilemma. Which book do I choose? Contemporary and easy to read or a classic that is more sci-fi??

xxOOxx