A series of overlapping and interrelated storylines about a group of kids in the small town of Seldom. Opportunities found and lost (mostly lost) and several clever asides and digressions.
Doesn't sound like much of a plot, does it? Well, it isn't. If this book had not just won the Newbery (and been written by a really great author), I'd probably just blow this one off as a bit of literary pretension. But instead I feel rather compelled to take it seriously, since others are as well.
There are a number of clever stories (the traveling necklace, the driving lesson, the guitar) and the writing is certainly excellent. There are also some really silly experiments (the sponge, the Japanese chapter). That said, I have a hard time seeing this as children's literature. Rather, it struck me as being as inaccessible as adult lit has become. Perhaps YAs would like it, but it is way too experimental and weird for younger readers and the vocab is a bit too advanced. Think The Little Prince with more SAT-level words. What you have here is a book written by adults for adults with the illusion of being a kid's book because the characters are children. But that doesn't make it a book for kids.
Now, if any young readers would like to weigh in and tell me I'm wrong, and that they really loved this book, I certainly wouldn't mind hearing from them, but my money is on the bet that this book isn't going to get read very much.