I'm proud to say that occasionally I have come up with completely new jokes all on my own. These are original to me, and they are my contribution to the world's joke supply. I tell them a few times and then they're on their own.
There's a good chance that this might be my most lasting contribution to humanity, so I figured I should record the ones I remember, starting with a knock-knock joke I invented for my nieces and nephews in Chicago.
"Knock knock!"
"Who's there?"
"To!"
"To Who?"
"No, to whom!"
What would happen if the Moth radio hour was sponsored by Caterpiller?
Did you hear about the warehouse clerk who became a famous chef? He had a highly developed palette.
Did you hear the rumors about incest in that family? The daughter takes after the father—literally!
Most families are a source of unconditional love. In mine, the prevailing goal seems to be unconditional surrender.
Did you hear about the strike at the playground factory? Employees refused to work the swing shift.
Variation
Why does the playground equipment cost so much? Because it's priced on a sliding scale.
Why was the woman who clipped coupons so unsuccessful? Because she had no redeeming qualities.