This might be interesting for some people (or maybe just to me!).
In probability theory, the birthday paradox states that given a group of 23 (or more) randomly chosen people, the probability is more than 50% that at least two of them will have the same birthday.
I'll assume that 23 will repond to this thread exactly giving their birthdate. If so there is a more than 50% that at least two of them will have the same birthday.
Amazing coincidence? Not so.
http://en.wikipedia.org/wiki/Birthday_paradox