Sal Selvaggio will never forget the first time he went bust. It was 12 years ago, late spring, back before he was Sal from madduxsports.com, back when he was working as an electrician outside Chicago. He wanted to be a professional sports bettor, the kind of guy betting 10 dimes a game, spending all day power ranking, analyzing data, finding an edge. He wanted his life to be full of electricity, not his job.

The man worked hard, saving his money, slowly building a bankroll that would let him take a bet out for a spin every once in a while if he happened to like it. Eventually, he had a nut of $5,000. It wasn't quit-your-job money, but it was enough to test out some theories.

"I started out real smart, being conservative. It was baseball season, and I was betting $100 or $200 a game," he says. "And I was winning; that's when I got overconfident."

Gambling 2 to 4 percent of his bankroll on a game wasn't good enough anymore. Why take it slow, like you would a still fragile and growing relationship, when he could double his bets and get wherever he was going a little faster?

Sal decided to start betting $300 to $400 a game instead.