Ding Dong, Who’s There?

Knock knock. Who’s there? Boo. Boo who? Aw, don’t cry! It’s just Tell A Knock Knock Joke Day! It’s also Doorbell Day, so should we be telling Ding Dong jokes instead? And when you go trick-or-treating, should you ring the doorbell, yell “Trick-or-treat,” or say “Knock knock”. I’m so confused!