I need quotes from Shakespeare in which he describes or comments on
the play of children.  I don't mean play in the grown-up sense of
sports or other organized activities.  It should be about children
(3-10years old)

I don't think you're likely to find what you're looking for in
Shakespeare. His few references to children's play tend to be rather
cynical, like this quote from "A Midsummer Night's Dream":

"As waggish boys in game themselves forswear, 
 So the boy Love is perjur'd everywhere" 

Or this, from "King Lear":

"As flies to wanton boys, are we to the gods.
 They kill us for their sport."

pinkfreud always is able to relate to shakespeare.  Thanks for the comment.