Gym-as-nightclub? Why not. Splashy, flashy, and oozing with South Beach flair, Miami’s David Barton Gym is the ultimate exercise in excess, featuring entrance-reflecting pools, valet parking, and live deejays (oh yeah, and 42,000 square feet of fitness space). With six ultra-luxe locations to his name, David Barton has clearly found his ($230 million) niche, and has no qualms about cashing in.