Things to do with Kids in NYC?
1. The Met - it really is like a playground for a kid (at least one old enough to know not to set off the alarms). The somewhat haphazard layout of the museum combined with the incredible amount of STUFF - from furniture to suits of armor to Egyptian temples to Medieval manuscripts to paintings - makes it a really great place for a kid to wander through. I think it's unfortunately overlooked that kids have a great sense of imagination and don't need toys or games all the time - the works in the Met are great imagination-fuel for a game of Pretend while the parents look at particular works of art... Plus, the nearby Ancient Playground, featuring climbable pyraminds and obelisks, is so darn cool!
2. The Carousel in Central Park
My grandmother took me here when I was younger and I loved it - and still love it! It's old-fashioned and sweet and altogether perfect.
3. Cedar Hill, Central Park
The best spot in the park to run, play, and otherwise just Be a Kid.
Any more suggestions?