I love John Green. He's so witty, his characters are real, and he's sometimes deep and philosophical in a way that I think teens like. This would be a great book to give to a graduating senior. 
 I'd been meaning to read this since I heard Wizard Rockers Matt Maggiacomo and Lauren Fairweather sing a song about it called "Peeing in a bottle" last summer. Their band together is called Armoured Bearcub. Teen lit rock, I guess.