With the Powerball jackpot swelling to $500 million, the largest in the lottery's history, ticket holders around the country are mulling a common, if almost impossibly fanciful, daydream: What do I do if I win?

First, the grim truth: The odds of winning the Powerball jackpot are roughly 1 in 175 million. To put that into perspective, the chances of getting hit by lightning in your lifetime is 1 in 5,000, according to Tim Norfolk, a University of Akron mathematics professor who teaches a course on gambling.