This came highly recommended by a children's librarian. Also, Laurie Keller is a favorite in this house (The Scrambled States is a MUST own book in any house with elementary aged children). She just *gets* what kids like to read. I would have LOVED this book as a kid - with its sly humor and tons of funny little details. I still love it now. My nine year old was crazy about it and insisted on reading the ENTIRE thing to me. This book is really ideal for independent reading, but it can work as a read aloud if the reader is super energetic and creative!
I hear that their is a new chapter book series based on Arnie - may have to check that out!