500 Days of Summer (2009)

Tom, the boy, still believes, even in this cynical modern world, in the notion of a transforming, cosmically destined, lightning-strikes-once kind of love. Summer, the girl, doesn't. Not at all. But that doesn't stop Tom from going after her, again and again, like a modern Don Quixote, with all his might and courage. Suddenly, Tom is in love not just with a lovely, witty, intelligent woman - not that he minds any of that - but with the very idea of Summer, the very idea of a love that still has the power to shock the heart and stop the world.