This article introduces an approach to service learning based on students' collective engagement with a range of community organizations. We explore the particular benefits of this comparative collective community-based (CCC) learning model through a discussion of the "Possibilities for Change in American Communities" program, which was begun by the authors in 2001. The program exposes students to a diverse set of community contexts by integrating a 32-day sleeper-bus trip around the eastern half of the U.S. into a year-long curriculum. We discuss the distinct advantages of such a program as well as the tradeoffs associated with the comparative analysis of multiple communities. We conclude by exploring alternative ways to incorporate the CCC framework within more conventional community-based initiatives.