A new wiki open to everyone who's interested in XP for any reason, but foremost folks trying to make XP work in the unique engineering milieu of SouthernCalifornia.
http://www.xpsd.org
The XpSanDiego ExtremeProgramming group meets once a month, usually the first Thursday. The mailing list is:
http://groups.yahoo.com/group/xpsandiego
Sam of XPSD has suggested someone print a tee-shirt with a GloballyUniqueIdentifier on it, such as 5C2673FC-B3AB-4973-8AE5-6ED0C9CB3475. Imagine the shock value!