Hats Off: Derby Fans Show Off Favorite Fashion AccessoryWearing hats to the Kentucky Derby is a time honored tradition that is believed to bring good luck.A fan arrives for the 141st running of the Kentucky Derby at Churchill Downs on May 2, in Louisville.Matt Slocum / APPrintMay 2, 2015, 5:29 PM UTC / Updated May 2, 2015, 7:07 PM UTC / Source: NBC News