The California's Outstanding Math Educators' Ongoing Network (COME ON) initiative is a unique and innovative effort to support high school mathematics teachers in California. It serves as a living example of a successful model that addresses an issue critical to all of mathematics education K-18--how to sustain and strengthen those most directly responsible for improving the quality of teaching and learning of secondary mathematics. COME ON is a statewide, curriculum-centric professional learning network. Its overall design is deliberately unlike other high school improvement efforts. It takes an original amalgamated approach rather than focusing on either a school or district level, or solely on traditional dimensions of change such as teacher enhancement, assessment or curriculum. Although centered on a specific high school instructional program--the Interactive Mathematics Program (IMP)--it builds upon and extends beyond the IMP work and its users, aiming to meet the needs of a broad range of California high school mathematics teachers, those who use the IMP materials and those who do not. COME ON provides a learning community for all interested high school mathematics teachers--offering them professional development, structures and venues for connecting with one another to discuss topics and issues related to classroom practice, as well as providing a range of leadership opportunities. This report provides what the authors think of as a "conceptual portrayal" of the COME ON initiative intended to highlight its significance and its future potential. They begin by recounting the genesis and evolution of the initiative. They then summarize the evaluation findings in terms of the value and impact of the effort, and go on to analyze the design components of the COME ON model. In the final sections, their aim is to bring a broader perspective and vision of COME ON to the reader in order to make the case for its potential contribution to state-wide mathematics education improvement. (Contains 2 footnotes.)