As part of the Foundations for Success in STEM project at Florida State University, more than thirty teams of teachers have used the Formative Assessment Collaborative Team (FACT) meeting model to work together toward better understanding of their students' mathematical thinking and its implications for instruction. This article provides a brief overview of the model and an account of a FACT meeting cycle in action. The article also reflects on essential elements of the FACT meeting model and teachers' perceptions of the impact that a yearlong commitment to participation had on their instructional practice. [The research reported here was supported by Grant Nos. 371-2355B-5C001 and 371-2356B6C001 to Florida State University from the Florida Department of Education through the U.S. Department of Education's MathScience Partnership program.]