Don't Knock It

On the way to the park, Ethan shared with me his personal discovery of "Knock, Knock, Who's There", jokes.

It started off with him asking "Knock, Knock!" Then I have to say "Who's There?". Then he says "Boo". Then I have to say "Boo, Hoo"?

Then he would scream with laughter and we would repeat it all over. Again and again and again.