Participants in the Prosocial Behavior Physical Activity (PBPA) intervention will receive a cognitive-behavioral intervention to teach participants the behavioral skills necessary to engage in long-term (12-month) independent physical activity. Participants in the Healthy Aging (HA) intervention will receive excellent educational sessions based on a number of topics of relevance to older adults. Both programs will provide supervised stretching sessions so that participants learn how to safely and effectively improve flexibility, which helps reduce the likelihood of falls and disability. However, the PBPA intervention will also allow participants to earn food for donation to Second Harvest Food Bank based on their regular physical activity and volunteer time.