Liberty State Park is an ideal way for families to spend the afternoon or evening overlooking Manhattan's landmark triumvirate (including the Statue of Liberty, Ellis Island, and the New York City skyline). The long boardwalk/pier is a great location to snap some photos (you'll feel like you can almost touch the Statue of Liberty). And it's also a great place for jogging or taking the little ones for a walk with your stroller.
Liberty State Park also has a robust event schedule, including a Kite Flying Festival and the popular annual Barkfest (for canine-inspired fun). Historical in its scope and reaching to the beautiful Central Railroad of New Jersey Terminal building at one end, this is definitely a place to wander, explore, run, and get lost.