Where superstition, gambling, and the stock market intersect: According to this article, Big Brown victory may spook markets, whenever a horse wins the Triple Crown, the stock market plunges for the rest of the year. However, when a horse that wins the Kentucky Derby and Preakness (as Big Brown has done so far) but LOSES the Belmont Stakes (to be run on Saturday), the market goes up.
So cheer for anyone but Big Brown. But if he wins, sell everything you have in the market, which, if everyone does it, would create a self-fulfilling prophecy.