Retro Fitness takes an old-school approach to its workouts—and its bright, primary-colored decor—but it's modern where it matters. The vintage nod comes from the no-frills style, which sees members enjoying classes, open gym time, and personal training in an approachable atmosphere. The machines, on the other hand, are cutting-edge, and trainers bring all the latest scientific wisdom to their sessions. Other ultra-modern amenities include the cardio movie theater, where an enormous screen beams films for the benefit of hardworking joggers. Plus there's a smoothie bar, where customers can savor protein-rich concoctions in an environment that resembles a 50's diner, checkerboard floors and all.