Juvenex Spa 
25 W. 32nd St., 5th fl., 646-733-1330
Like the area's nightclubs and late-night eateries, Juvenex Spa is a natural addition to this caffeinated part of town. The spa, open 24/7, is tucked away in an office building. It's ladies-only from 7am to 5pm, but Juvenex becomes coed in the evening, making it a popular spot for Broadway actors and dancers winding down after a performance. Standard spa treatments like facials, massages and body wraps are offered, but regulars praise the Japanese-style soaking ponds—infused with ginseng, sake and algae—and the jade igloo sauna. The spa also serves as the setting for a great date night, with affordable couples packages and private massage rooms.