For instance, on the planet Earth, man had always assumed th... - Douglas Adams, The Hitchhiker's Guide to the Galaxy

"This must be Thursday,' said Arthur to himself, sinking low over his beer. 'I never could get the hang of Thursdays."

"We demand rigidly defined areas of doubt and uncertainty!"

"The Ultimate Answer to Life, The Universe and Everything is...42!"

"This planet has - or rather had - a problem, which was this: most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movement of small green pieces of paper, which was odd because on the whole it wasn't the small green pieces of paper that were unhappy."

"Exactly!"said Deep Thought. "So once you do know what the question actually is, you'll know what the answer means."