For those kids interested in math, though they may be few, the Flatiron District's Museum of Mathematics is the only museum of its kind in America.  From tricycles with square wheels to 3-D printers, this recent addition to the New York children's museum scene may be a little rough around the edges but is an undoubtedly good time for kids age 6 and above who love numbers and patterns.  Admission is 15USD.

momath.org