The average gym can be so depressing: It smells all sweaty, it's noisy and dim—you're lucky if you can find a few meager rays of sunlight. New York Health and Racket in Chelsea has a rooftop sun deck that's not only big enough for you and a number of friends to hang out and tan au naturel; it's also separated from the gym by glass, making it a choice spot for voyeurs who have a thing for tight abs and rock-hard buns. Members can grab towels and chill out on lounge chairs for hours, and if it gets too hot, they can take a dip in the nearby glassed-in pool, then saunter right back into the sun. The gym is open until 11 p.m., so you can relax out there until sundown and then skip off to the sauna. Can't beat that.