What does 42 mean?
"Forty-two,” said Deep Thought, with infinite majesty and calm.
It was a long time before anyone spoke. Out of the corner of his eye Phouchg could see the sea of tense expectant faces down in the square outside.
“We’re going to get lynched aren’t we?” he whispered.
“It was a tough assignment,” said Deep Thought mildly.
“Forty-two!” yelled Loonquawl. “Is that all you’ve got to show for seven and a half million years’ work?”
“I checked it very thoroughly,” said the computer, “and that quite definitely is the answer. I think the problem, to be quite honest with you, is that you’ve never actually known what the question is.”
“But it was the Great Question! The Ultimate Question of Life, the Universe and Everything!” howled Loonquawl.
“Yes,” said Deep Thought with the air of one who suffers fools gladly, ”but what actually is it?”
A slow stupefied silence crept over the men as they stared at the computer and then at each other.
“Well, you know, it’s just Everything . . . everything . . . ” offered Phouchg weakly.
“Exactly!” said Deep Thought. “So once you do know what the question actually is, you’ll know what the answer means.”
-Hitchhiker's Guide to the Galaxy, by Douglas Adams, published by Ballentine Books, 1980, page 181-183