Inside a one-story building on the edge of a strip mall in Central Florida, Joy Baker calculates the sum total of her morning bets. It's almost noon, and she's down $5. Not bad. Her husband, Tony, sits a few feet away. "This is the most fun we've had in 20 years," says Joy, who is 78 and retired. "At our age, we can't hike. You can't pay him to go to the movies. This gives us a reason to get up in the morning."