The communist parts of the world recycled all sorts of jokes. See a few here, as nicely reviewed here.

Some of them maybe emerged elsewhere back in the mists of time and were rebooted for new purposes.

Thus:

"A Russian proverb: If you see a Bulgarian in the street, beat him. He’ll know why!"

When I shared that with someone in Poland he said he’d heard it long before in the Middle East, but with the words "your wife" replacing "a Bulgarian".

Or this one:

A Pole, a Nigerian and a Russian are standing outside the hospital ward where their respective wives have just had their respective babies.

Out comes an agitated nurse. "There’s been a mix-up. We don’t know which baby belongs to whom!"

The Pole says that he will sort things out and enters the ward. He reappears with a strikingly dark-skinned African-looking baby.

"The Nigerian coughs politely. "Excuse me, but perhaps that one is mine?"

Pole: "Look, there’s a Russian in there and I’m taking no chances!"

That one is found on the Internet in numerous ethnic and other forms. It is a fine one to use to unnerve clever people from Harvard.

They laugh nervously, shocked at its apparent racially charged political incorrectitude but unable to work out why it is offensive and to whom.