Overtown is a slum and the last place you'd expect to see real estate whiz, revered art collector, and poster man for the rich and powerful Marty Margulies. But there he was one day, noticing how kids on NW Fourteenth Street were hanging and banging, preparing for a future in dope slinging or gangsta pimpin'. Some may have been plotting escape, but that's a lofty dream down here. Margulies -- a rare if not unique mix of developer-smarts and goodness-of-heart -- whipped out $2.5 million and had built the terrific 18,000-square-foot complex known as the Overtown Youth Center. About 200 children have joined the new facility, which boasts spiffy classrooms, a fine auditorium, lockers, showers, computers, and the best basketball court in town. Alonzo Mourning, who appeared at the center two months and two days after a kidney transplant to speak to the children, has used his charities to fund day-to-day expenses. Only children who are members of the center's after-school program can use the gorgeous court, but they play teams from around the county and anyone can attend. Also, the OYC is part of Gibson Park. Walk past the Chinese restaurant and the church, across the park's grassy knoll, and, at the southern end, you'll find excellent courts where anyone can play.