There's no better place for a little friendly competition than the Chelsea Field House. Birthday boys and girls (ages 5 and up) choose one or two of their favorite sports to play. Options include traditional picks such as soccer, dodgeball and basketball, learning how to flip and tumble with gymnastics, scaling a gigantic rock-climbing wall or challenges like parkour with a “Ninja Warrior” theme or a collection of classic field-day games like tug-of-war and potato-sack races. All packages feature time in the party room with venue-supplied balloons and paper goods, but parents looking for a hassle-free occasion can also opt to have pizza, beverages, cake and party favors handled by Chelsea Piers. Score! Ages 1 and up.