Tyler Cowen notes that there is the opportunity to earn yourself an Erdos number up for sale at E Bay.For a full description of what this means follow his links.
On asking the Maths correspondent of this blog what he thought, and what his Erdos number was, I received this response:

I knew Paul Erdos. He visited Houston while I was an undergraduate. He kept asking me to score speed for him, I’m glad to say I don’t have an Erdos number.

So an Erdos number is not for everyone then.