After having their 11th child, an Irish couple decided that
that was enough, as they couldn't afford a larger bed.
So the husband went to his doctor and told him that he and
his wife didn't want to have any more children.
The doctor told him there was a procedure called a vasectomy
that would fix the problem but it was expensive. A less
costly alternative was to go home, get a large firecracker, light it,
put it in a beer can, then hold the can up to his ear and
count to 10.
The husband said to the doctor, "B'Jayzus, I may not be the
smartest guy in the world, but I don't see how putting a
firework in a beer can next to my ear is going to help me with my
problem."
"Trust me, it will do the job", said the doctor. So the man
went home, lit a cracker and put it in a beer can.
He held the can up to his ear and began to count: "1, 2, 3, 4,
5," at which point he paused, placed the beer can between his legs so
he could continue counting on his other hand.
This procedure also works in New Zealand and Australia.