Take your family hiking in one of the loveliest areas of Central Park, the Ravine, with the National Wildlife Federation, which is holding similar outdoorsy happenings in cities across the country to foster in kids an appreciation of nature. You'll meet along Central Park's west side (between 100th and 103rd Sts) between 9 and 10am, where different hiking groups will be sent out at staggered times. Note that the one-mile path is not stroller-accessible. Space is limited and advance onlline registration is required. Ages 3 and up.