I am not very sure about the translation of that sentence from Nietzsche. I translated from Portuguese maybe the sentence should be:
In every real man a child hidden that wants to play or In every real man a hidden child that wants to play.
I looked for the sentence in English but didn't find it.
And about playing, we are fortunate children that can play George, there are a lot of children being abused, working or serving Lords of war or other very bad things, denied from the childhood they are entitled, my main frustration is I can not do much about it.
Is a bad world for some and we are the lucky ones, something we all must be very aware of.