Carla Davidson

Once upon a time, New York City's telephone exchanges were instant social arbiters. When you dialed BU-8 (Butterfield 8, as in the novel and film), you knew you were calling someone in the most desirable section of the Upper East Side, encompassing Fifth, Madison and Park—perhaps Lexington—from 86th Street to the low 60s. In the 1960s, digits replaced the exchanges, and while there is no thrill in dialing 288, the neighborhood remains home to some of the richest New Yorkers: Think Mayor Bloomberg, Caroline Kennedy and, of course, the Gossip Girl crowd. Even though little trace remains of the Astors' and Carnegies' early-20th-century mansions, take a walk around these parts and you'll still feel that old-time, uptown charm thanks to the distinguished prewar apartment buildings on Park Avenue, the low-rise townhouses turned high-end clothing shops on Madison Ave and the grand museums on Fifth Avenue. To find resources such as gyms, play spaces and movie theaters, you'll have to head east toward the river. Check it out The China Institute (125 E 65th St, 212-744-8181) is one of the city's least explored treasures. Sign up your three-year-old for a Chinese language class, or take part in one of the special family workshops keyed to major Asian holidays and festivals. The children's program "Start with Art" is free with admission to the Metropolitan Museum of Art (1100 Fifth Ave, 212-535-7710). It's a perfect way to introduce your tykes to this world-renowned collection. Afterward