Welcome to 54,000 square feet of everything you could ever want in a gym; a shrine to fun that is equal parts adult playground and totally kick-butt gym. From quirky extras to equipment that most gyms just don’t have (a three-story indoor slide, swimming pool, large sun deck for catching rays etc.) North Ave. is one-stop-shopping for those in the market for workouts that are so much fun, they hardly feel like work.