jargon.artrocity.com
New Hacker's Dictionary the Jargon File v 4.4.6
[TMRC] For any story, in any group of people there will be at least one person who has not heard the story. A refinement of the theorem states that there will be exactly one person (if there were more than one, it wouldn't be as bad to re-tell the story). [The name of this theorem is a play on a fundamental theorem in calculus. —ESR]