Colt's 1st Joke

This afternoon Colt told his 1st joke. It came out of the blue, he was coloring and Tom and I were writing a grocery list. Here's his joke:
Colt "Knock, knock"
Us "who's there?"
Colt "Orange"
Us "Orange who?"
Colt "Banana!"

He was so anxious to hear us laugh. Then, of course, he told it again and again and again. 4 1/2 is such a great age.