Question of the Week: Have You Secretly Enjoyed a "Kids" Book?

The Wall Street Journal and Publisher's Weekly have both recently highlighted a trend of adults reading books marketed to middle school aged children.  As the WSJ article mentions:

Some children's-book authors are deliberately shaping their books for adults. Mr. Kinney, author of the mega best-selling series, "Diary of a Wimpy Kid," said he first envisioned his illustrated books about a middle-school kid named Greg as wry cartoons for adults. His first draft was 1,300 illustrated pages. His publisher, Abrams, convinced him to target kids, arguing that the sassy young narrator would appeal to children, and adults would follow. 

Personally, I couldn't agree more that books that are supposed to be for fifth and sixth graders are some of the most delightful reads out there, especially in the fantasy and historical fiction genres. Do you have a favorite kid's book that you have enjoyed as an adult, or that you know an adult has enjoyed?

Palacio, R. J. Wonder. Alfred A. Knopf, 2012. 

Ten-year-old Auggie Pullman, who was born with extreme facial abnormalities and was not expected to survive, goes from being home-schooled to entering fifth grade at a private middle school in Manhattan, which entails enduring the taunting and fear of his classmates as he struggles to be seen as just another student.

Sage, Angie. Physik.  Katherine Tegen Books, 2007. 

Pulled through a glass that brings him back in time, Septimus Heap becomes the apprentice of an alchemist.