Your favorite ending you never saw coming

I am often disappointed in books that have very obvious twist endings...you know, those occasions where the clues are obvious and the twist so cliché that you know it's gonna happen before it happens. But every once in a while a there's an ending that totally catches me off guard yet when I look back at everything I've just read, totally makes sense. I love it when that happens.

So, in the spirit of that thought, what are some of your favorite books with endings you never saw coming?

Burned by Ellen Hopkins;
also, Impulse by Ellen Hopkins.
:)

Tigana by Guy Gavriel Kay - it always makes me think about what lives the characters will have after the ending of the book.

Iodine by Haven Kimmel

Utterly fabulous!

I agree with >3 ryn_books:. Also just finished Stone's Fall, and didn't see that one coming!