What’s the last thing you stayed up half the night reading because it was so good you couldn’t put it down?
I think the last book that had me wanting to stay up late to finish was Dark Fire by Chris D'Lacey (my review).
I think of it now and some of the book is really complex but that parts that weren't were the parts that had me wanting to read more. Which were the parts about the characters. Since this was a book from a series (#5 of 7) I was returning to old friends and some of them were growing up and it was as exciting for them as it was me.