Slava Boxing Gym & Heights Fitness, Houston

The stiff white collar that comes with an eight-hour-a-day desk job can feel pretty stifling. Steve Kozakov opened Slava Boxing to help America's office workforce cut loose, beating stress and inactivity in his high-energy boxing classes. Steve sticks to the classic training principles and exercises that professional fighters use when getting in the ring, though there's one key difference: He never expects his students to actually fight. Instead, he treats his regimens as a fun way to get into shape, make a few friends, and blow off some pent up steam, preferably while releasing the long, high-pitched scream of a teakettle on the hunt.