An Irishman caught a leprechuan and was offered three wishes if he would release the leprechuan. He decided that he could really use a beer so he made that his first wish.

A mug of beer appeared on a rock so he drank it down. As he prepared to make his second wish, he noticed that the mug was full of beer.

How did that happen? he asked.

The leprechuan explained that for as long as he lived the mug would be full and he could drink all he wanted.

The Irishman said, In that case, Ill take two more of those!