An old Jewish man reads about Einstein's theory of relativity
in the newspaper and asks his scientist grandson to explain it to him.
"Well, zayda, it's sort of like this. Einstein says that if
you're having your teeth drilled without Novocain, a minute seems like
an hour. But if you're sitting with a beautiful woman on your lap, an
hour seems like a minute."
The old man considers this profound bit of thinking for a
moment and says, "And from this he makes a living?"
-- Arthur Naiman, "Every Goy's Guide to Yiddish"