An Abundance of Katherines by John Green
Colin Singleton is a teenage prodigy who has just graduated from high school. He has also just realized the difference between a prodigy and a genius ("Prodigies can very quickly learn what other people have already figured out; geniuses discover that which no one has ever previously discovered. Prodigies learn; geniuses do.") He has also just been dumped for the 19th time by a girl named Katherine. Not the same Katherine -- nineteen different Katherines.
To roust Colin from his deep funk, his best friend, Hassan, proposes a road trip. And thus, the socially maladjusted brain and the overweight underachiever find themselves in Gutshot, Tennessee*, drawn to this particular exit by an unlikely road sign that reads, "See the Grave of Archduke Franz Ferdinand -- The Corpse That Started World War I."
Before they know it, Colin and Hassan find themselves with a place to stay for the summer, a job collecting oral histories, and a mathematical equation that predicts the course of relationships along a Dumper/Dumpee continuum. And of course, a great deal of the obligatory YA novel self-exploration and soul-searching to be done... although done in an illuminating and not at all sappy sort of way.
An Abundance of Katherines is excellent. It's smart and funny, filled with thorny, yet endearing characters, and addresses big issues with a light touch.
If you liked...: King Dork by Frank Portman or Boy Proof by Cecil Castellucci, this book is for you.
* I wonder if this town name was inspired by Bucksnort, Tennessee, a place I once stopped on a road trip sheerly because of the name.