What does it take for everyone to say enthusiastic “Yes!” to learning mathematics? If learners have been forced before, how do we help them recover from the experience? The promise of open source is that everyone has sources available to make something. That is an excellent analogy for the Natural Math approach to building mathematical knowledge. If learners have full access to sources of their math, such as wondering, noticing, modeling, and problem-posing, then they can make their own math – and, in the process, make math their own. Learners become makers of mathematics. What does that imply for curriculum development? We need to re-examine some of the most fundamental assumptions about teaching and learning. What if we go beyond the linear sequence of topics, and make all sixty-three major subject areas of math (topology, calculus, combinatorics, and so on) available from kindergarten on, in the same way Montessori approach makes several tasks at a time available to students? What if instead of training students to fit into a math course, we start from each student’s passions and interests, then find which math topics fit the student? What kind of concerted, community-wide, open effort does that vision require – what tools, know-how, and support infrastructure? The talk will present working prototypes and possibilities for the wider implementation.