"Seamus & the Genie" joke

Seamus was walking along the coast of Galway early one morning with a bit of a sore head when he tripped over something in the sand. Reaching down, he picked up a lamp and starting rubbing it. There was a huge crack of thunder, an awesome amount of smoke, and lo and behold, a genie appeared.
"Mornin' boyo," said the genie. "For releasing me from two thousand years of bondage, I'll be grantin' ya three wishes."

"Isn't this grand," said Seamus. "Can I have a pint of Guinness?"

"Sure of course ye can," said the genie. And poof! a pint appeared in Seamus's hand. Seamus starting sipping away at the pint. "For the love o' Jaysus, this has to be the best pint I've ever been tasting."

"Of course it is," said the genie. "I'm an Irish genie, after all, and I do know a bit about pints. Now, let's get on with business. You've got two more wishes left, and I haven't got all day!"

"Now just be bidin' yer time," said Seamus. "I want to enjoy me pint."

"Ah," said the genie. "That's a magic pint."

"And what do ye be meanin' by that?" asked Seamus.

"Well," said the genie, "as soon as it's done, it'll fill right back up again just as good as the first."

"Is that so," said Seamus, finishing off the pint. Sure enough, back up it came, and when he tasted it, it really was every bit as good.

"Now," said the genie, "about those other two wishes?"

"Ah," said Seamus, "I'll have two more o' these!"