AI curricula are being developed and tested in classrooms, but wider adoption is premised by teacher professional development and buy-in. When engaging in professional development, curricula are treated as set in stone, static and educators are prepared to offer the curriculum as written instead of empowered to be leaders in efforts to spread and sustain AI education. This limits the degree to which teachers tailor new curricula to student needs and interests, ultimately distancing students from new and potentially relevant content. This paper describes an AI Educator Make-a-Thon, a two-day gathering of 34 educators from across the United States that centered AI curriculum co-design as the culminating experience of a year-long professional development program called [anonymized] in which educators studied and practiced implementing an innovative curriculum for [anonymized] in their classrooms. Inspired by the energizing and empowering experiences of Hack-a-Thons, the Make-a-Thon was designed to increase the depth and longevity of the educators’ investment in AI education by positively impacting their sense of belonging to the AI community, AI content knowledge, and their self-confidence as AI curriculum designers. In this paper, we describe the Make-a-Thon design, findings, and recommendations for future educator-centered Make-a-Thons.