In addition to the member discounts and benefits such as insurance, AARP is a strong advocate for the rights of seniors. AARP offers many educational programs, such as defensive driving and financial literacy. In partnership with the IRS, AARP Tax Aide certified volunteers offer free income tax preparation for those who have low to moderate income and seniors.
My aunt is a member and highly recommends it. I've been encouraging the grumpy guy to join. 
MM
"Our past is a story existing only in our minds. Look, analyze, understand, and forgive. Then, as quickly as possible, chuck it." ~ Marianne Williamson