Alternatives to AARP
— Association of Mature American Citizens http://www.amac.us/
— American Seniors Association http://www.americanseniors.org/
— The 60 Plus Association info@60plus.org
There is also a new organization called Generation America, (generationamerica.org) which says "We focus our efforts on protecting and promoting our individual freedoms so that we can continue living active and fulfilling lives...Join us and become part of an over-50 community united in its defense of individual liberty and freedom."
My tagline has been the same for several years (except the age changes...).