I just finished The Mysterious Benedict Society yesterday and was greatly impressed.
The style of writing was definitely that of a children's book, but is much more compelling and well crafted than most. The story is about a team of four unusually talented children who are brought together by a genius to prevent an unknown catastrophe.
Trenton Lee Stewart crafted a very intriguing and satisfying book. It is a fairly quick read and I highly recommend you pick it up. It is one of the better things I've read lately.