From 'Overheard in New York':
Mom to four-year-old being picked on by brother: Tell him to leave you alone.
Four-year-old: Leave me the fuck 'lone!
Mom: Hey! Watch your mouth.
Four-year-old: I'm gonna fuck 'im up.
--Staten Island Ferry
No idea what came first: 'The Man who fell asleep' or 'Overhead in New York', but they are both equally funny.
Hat tip to Kara.