If you haven't been to Madison Square Park with your kids, then you should go right away. But if you need a reason to get you there, then this is definitely it: Every Tuesday and Thursday mornings through the summer they have free shows for kids.
There are some great performances too. Tomorrow Audra Rox, who is breaking out big time in children's music, will be performing. We saw Dan Zanes for free, up close and personal there a couple of years ago. It's like Irving Plaza; kids can rock out within spitting distance of their favorite musicians and performers--only it's free, outside and the most popular mood altering chemical is sugar.
Madison Square Park also has a fantastic playground with a water feature and, of course, the famous Shake Shack which serves up hot dogs, burgers and shakes to die for. Enough to make it a great destination whether you go for the free kids concerts or not.
Check out the full schedule for Madison Square Kids free summer performances.