I went to the Storm King Art Center last week end, and discovered one of the most amazing collection of (huge) sculptures I've ever seen. You can easily spend the whole day in this wide and very well maintained park
I'm surprised it's not mentioned in any of the guide of NY I own. One hour and a half from NYC, it's really worth the trip. Especially for fall as the colors are sumptuous. Definitely kid friendly, as well.
Widely celebrated as one of the world’s leading sculpture parks, Storm King Art Center has welcomed visitors from across the globe for fifty years. It is located only one hour north of New York City, in the lower Hudson Valley, where its pristine 500-acre landscape of fields, hills, and woodlands provides the setting for a collection of more than 100 carefully sited sculptures created by some of the most acclaimed artists of our time.