While the exact origin of the term dad joke is unknown, a writer for the
Gettysburg Times wrote an impassioned defence of the genre in June 1987
under the headline "Don't ban the 'Dad' jokes; preserve and revere
them".
-Wikipedia
Did you hear the joke about the roof? Probably not. It's over your head.
Did you hear the one about the bed? It hasn't been made up yet.
But seriously, do you know if it is vegetable root season yet? Because it is time to TURNIP!