If you're attending the Kentucky Derby this weekend — or simply looking to channel the same Southern style at whatever themed fete you've got planned — you are going to need the perfect dress. The brighter and more flowery the better, in our opinions, but it's best to settle on an option you can wear well past the last horse race. We've scouted the frocks . . . all you'll need now is the perfect hat and, of course, an ice-cold mint julep.