A former professor of mine grew up with Paul Erdös frequently living at her house. Her father is a prominent graph theorist and has 50 papers with Paul Erdös. Ordinarily she would have Erdös number 2 through several papers with her dad, but has been granted an honorary 1.5 because she also washed his clothes.
That link didn't work for me - locale problems - but this one does:<p><a href="http://en.wikipedia.org/wiki/Erd%25C5%2591s_number" rel="nofollow">http://en.wikipedia.org/wiki/Erd%25C5%2591s_number</a><p>I have an Erdos number of 2, and remember being unreasonably delighted to discover I have an Edros number of the second type of only 3. I thought it would be much bigger.<p>Not that it really means anything, but it would now be cool to appear as an extra in a Kevin Bacon movie ...
For those of you unfamiliar with Paul Erdős and who are interested in learning more, I highly recommend the biography "The Man Who Loved Only Numbers", by Paul Hoffman. He was such a quirky and unique character that his story makes a great read (even for non-mathematicians).
For all his brilliance, Erdos was unable to answer the Monty Hall Problem correctly: <a href="http://en.wikipedia.org/wiki/Monty_Hall_problem" rel="nofollow">http://en.wikipedia.org/wiki/Monty_Hall_problem</a>.<p>For those who don't know it, the problem requires no math except a <i>very</i> basic grasp of probability. Personally, I find it somewhat absurd that you can be considered a mathematical legend but still miss that problem. I think it even took Erdos some time (months) to accept the solution, but I don't have a citation for that.<p>He's not alone, either. Lots of mathematicians miss that problem, which makes me wonder about the fundamentals of a Math education.