A broke guy walks past a pub. He looks at the door longingly, but since he has no money, he walks on. Just then, he spots a lamp lying in the gutter. He picks it up and rubs it, and a genie emerges.
“I will grant you three wishes,” intones the genie.
“Give me a bottomless mug of beer,” the guy says.
A mug of beer appears in his hand. He takes a sip, then another. With each chug, the mug magically refills.
“And for your other two wishes?”
Between swallows, the lucky guy shouts, “Give me two more just like this one!”