Scientific American: Imagine you are on vacation and find yourself running low on a few necessities. You stop by a small convenience store to stock up and are immediately faced with the usual suspects: cramped aisles lined with chips and candy, a beer cave in the back, an oddly placed rack of discount t-shirtsand a lottery showcase behind the countera veritable gamblers paradise. Normally you wouldnt play; today, however, youre overcome by the urge to try your luck. But what game do you choose? Do you select among...