CCP 1264     

Art. 1264.  Unincorporated association

Service on an unincorporated association is made by personal service on the agent appointed, if any, or in his absence, upon a managing official, at any place where the business of the association is regularly conducted.  In the absence of all officials from the place where the business of the association is regularly conducted, service of citation or other process may be made by personal service upon any member of the association.