Why 42?

"Though I don't think," added Deep Thought, "that you're going to like it."

"Doesn't matter!" said Phouchg. "We must know it! Now!"

"Now?" inquired Deep Thought.

"Yes! Now..."

"Alright," said the computer and settled into silence again. The two men fidgeted. The tension was unbearable.

"You're really not going to like it," observed Deep Thought.

"Tell us!"

"Alright," said Deep Thought. "The Answer to the Great Question..."

"Yes!.."

"Of Life, the Universe and Everything..." said Deep Thought.

"Yes!.."

"Is..." said Deep Thought, and paused.

"Yes!.."

"Is..."

"Yes!!!?.."

"Forty-two," said Deep Thought, with infinite majesty and calm.