Knock knock. That's the classic joke set up, quite literally like a stranger at your door who will certainly deliver a groan-inducing pun once you respond. For more than 100 years this type of "nifty" joke has traveled a repeating orbit of American humor popularity, from beginning as an explosive white-hot hilarious craze to eventual pseudo-scientific denunciation as an obsessive psychological illness, and back around again.
So... who's there?
Don.
Don who?
Don you like the joke?

01.21.20