Two thieves break into a bank in the middle of the night and open a safe. There is only some yogurt, but no money. They taste the yogurt. It's tainted.
The men open the next safe.
There is some yogurt too, it tastes much better but again - no money.
The thieves take on another safe. And there's yogurt again.

"John, why don't you go outside and look if it is indeed a bank!" says one to the other, and sits down to eat the yogurt which tastes really fresh and nutritious this time.

A couple of minutes late there comes John. "It is definitely a bank!"
"What exactly did the sign say?"
"The Sperm Bank of Ohio!"