This article features Language Partners, an ESL program offered at the Danville Correctional Center, a medium-security men's prison in central Illinois. The program in which prisoners teach ESL classes, supported by volunteer teacher-trainers, is a learning community with immense and sometimes unforeseen value. The authors discuss reasons for teachers (and learners) to participate in the program, and they illustrate the remarkably collaborative nature of the teaching and learning. They then reveal the unexpected benefits of Language Partners, namely, its effect on relationships with family members and on perceived stereotypes of prisoners. They conclude by reflecting on the program's challenges and accomplishments and consider implications for its wider adoption. (Contains 2 figures and 1 note.)