Just finished The Hunger Games trilogy. Burned through them at a lightning-fast pace (like a-book-a-day fast) eagerly gobbling up each delicious page.
This series was incredibly mature for a children's books. I don't know whether I'd ban my little sisters (8 & 10) from reading it or make it immediate required reading. Thankfully I don't make that decision. Harsh but good lessons to be learned here.