Community activities, especially those that bring together people of all ages, seem to be increasingly rare and brief lived in this busy world. Yet they provide a lot of meaning in people's lives, for reasons ranging from the deeply personal to the broadly impactful. I used to volunteer for the San Francisco Symphony, selling discounted concert tickets to college students. This activity brought together people of all ages to contribute to the survival of the arts, and to learn from one another about topics ranging from fundraising to musical composition to the role of music in health. And it yielded many enduring friendships, formed in the act of pursuing a common goal. From this experience and others, I learned that community participation in an activity gives people a stake in it, ensuring its endurance and prominence. It also increases the diversity of people who contribute to the activity, beyond just the specialists, thus broadening the scope of the activity and increasing its power and relevance. Finally, such activities enrich the meaning of the lives of the people participating, enabling them to contribute to the well-being of the world and building communities of interaction and support, which is perhaps why the absence of such activities in one's life can be palpable at times. ...