In last week's CelebStyle Smarts quiz, most of you knew the difference between Mary-Kate and Ashley Olsen's style. Go you! As exemplified here, MK is the sister that doesn't mind looking a little tousled, and we appreciate her for that. The vintage Halston black bat-wing caftan she wore to the Late Show is floaty and flirty. She accentuated her tiny waist with a studded belt and fancied her feet with a pair of Louboutin pumps. Of course, she couldn't leave home with her signature small round sunnies.