Central Park

• One of the best places to keep children active in New York City is Central Park. You can visit 21 different playgrounds, climb the natural boulders in the park, ice skate at two outdoor rinks in winter, or swim free at the outdoor pool in summer. Rent a rowboat from the boathouse, or rent a bicycle and cycle along the bike path. You can play ball or Frisbee just about anywhere you find a patch of green.
  
  

Chelsea Piers

• Chelsea Piers, on the west side of Manhattan, offers sports for children ages 12 months to 17 years old. Preschoolers can choose gymnastics, micro-soccer or dance, or a session at the Little Athletes Exploration Center. Kids ages three to 17 can choose baseball, basketball, bowling, dance, golf, gymnastics, ice hockey, ice skating, rock climbing and soccer. Chelsea Piers also offers Youth Fitness classes. Bluestreak sports performance training lets kids work with personal trainers to up their game in a variety of sports.
  
  

Liberty Science Center

• Liberty Science Center, in Jersey City, New Jersey, has several floors of interactive exhibits. If your kid isn't claustrophobic or afraid of the dark, he should head to the Touch Tunnel line. Kids under age 7 can crawl through the tunnel with a parent. At the Skyscraper! exhibit, walk down a 20-foot long wind tunnel, balance on a thin steel beam 18 feet in the air or build a city. In summer, head to the outdoor exhibit, Wildlife Challenge.
  
  

Brooklyn Boulders

• Brooklyn Boulders, in Park Slope, Brooklyn, is New York City's largest climbing gym. Regular climbing is open to kids 4 and older. Children's classes include an after school Kids League for kids ages five to 10. Children focus on stretching, climbing games, roped climbing, and slack lining. The Teens League, for ages 10 to 16, concentrates on climbing and belaying. Both programs run on a drop-in basis, so you don't have to commit to a class.