This is another Newbery winner that I listened to with my son on our road trip. We enjoyed this one even more than Bud, not Buddy.
Banished from his mouse community for fraternizing with humans (to borrow C.S. Lewis's phrase), Despereaux is sent to the dungeon where it is assumed he will be eaten by the rats. Of course, he isn't eaten by the rats, but while he's in prison he learns of a rat's plans to harm one of his beloved human friends, Princess Pea. His quest to save the Princess Pea forms the rest of the story, which I won't spoil for you!
This is a very charming fantasy tale that kept us truly entertained on our trip. It might be a little scary for those under 8 or so, though. I also recommend DiCamillo's The Miraculous Journey of Edward Tulane, which I read and enjoyed earlier this year.
2003, 272 pp.