Churchill Downs, the owner of the world-famous Kentucky Derby, is in one of the best positions to profit from legalized sports betting.  Churchill Downs already has one of the top online-sports wagering websites, TwinSpires, but they also own numerous horse racing tracks and six casinos.  Churchill Downs is already looking beyond horse racing, and they have decades of expertise in online betting to bring into the newly opened sports betting market.  Churchill Downs' existing client base, political clout, and deep pockets will make it a challenge that any emerging player in the market should watch out for.