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Leave the helmet head to the cast of Mad Men. Celebs like Ashley Greene are intentionally wearing tousled hairstyles everywhere from ball games to the red carpet for a playful, sexy look.
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Marisa Miller
The Victoria's Secret Angel wears a trendy side braid with her shorter layers casually slipping out at a baseball game.
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© Mark Sullivan/WireImage

Marion Cotillard
The French screen star gives her tightly curled bob some intentional frizz and a center part.
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Ke$ha
Here's an example of going intentionally messy, but not keeping it classy. Ke$ha likes to err on the side of "hot mess" rather than "elegantly and artfully tousled."
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© Amy Sussman/Getty Images