Though New Yorkers can't ride the waves at Rockaway Beach year round, this comes close. By balancing on a wobbly board, you learn the movements, rhythm and tricks you’ll need to stand on an actual surfboard—all while you’re still on dry land in a NYC studio. All the core strength and balance it requires to stay upright translates into a killer workout. That must be why surfers generally have such incredible bodies, huh? Once you manage to calibrating your body and “cut waves"—cowabunga, dude. $25–$32.