(Photo: Melissa Hom)

Duchess
We wanted to create a refined, Victorian-style costume (à la Keira Knightly in The Duchess), mostly because it provides an excuse to wear a traffic-stopping hat. We browsed an array of high-collared, ruffled shirts at Physical Graffiti before settling on this delicate silk number ($88) and added a pair of gussied-up opera gloves from Pippin Vintage Jewelry ($18). Take the look a step further at the Family Jewels, where you'll find rows of nineteenth-century cotton underskirts and bloomers— plus a covetable stash of feathered, veiled, and bejeweled hats, like this wide-brimmed style on Carey ($69).

Police Officer
The shirt is an official-looking find from Star Struck ($26), where the owners have been vintage collectors for 28 years. Dress up as a generic city cop, like Mike, or muster a Fu Manchu and go as Seth Rogan from Superbad. We appreciated the dated look of this Screaming Mimi’s hat ($28), though we also spotted a more modern version at Love Saves the Day. And no police ensemble would be complete without some no-nonsense, slightly ironic shades, like this pair from Fille de Joie ($60).