It’s complicated but engaging — in the weeks leading up to the third Fashion’s Night Out (that yearly September evening of late-night shopping and in-store parties that takes place in cities all over the world) Vogue will sponsor a FNO-themed styling contest in conjunction with style site Polyvore.  The contest, FNO Style Setter, kicks off on August 15 on a designated Polyvore page.

Specific challenges will change each week, and so will the judges.  After Vogue editors pick the best outfit submissions on a daily basis, Grace Coddington, Alexander Wang, and Blake Lively will each take a turn judging the two best looks of the week.  Voting for the final winner is open to the contest’s entire audience.  Meanwhile, the challenges themselves are themed along the lines of ‘What to Wear on FNO’ and ‘Dress a Style Icon for Fashion Week.’ All outfit submissions must include a piece from the Fashion Night Out collection or show the FNO logo.  How’s that for a smart use of your-audience-as-marketing-tool?

The prize is ultimate fan engagement with Vogue, in the form of a trip for two to New York, access to one of the magazine’s photo shoots, and a tour of Vogue‘s fashion closet.  This is so clever — FNO may only take place in a few American cities, but this is a great interactive way to get fans all over the country involved.  The contest also deserves props for drumming up positive attention for FNO itself, which, on the eve of its third year in existence, is quickly turning into an institution.