In this study we introduce "lesson play experience" (LPE) for implementation as professional development for in-service teachers. LPE is an extension of the "lesson play" notion, which refers to a script for an imagined lesson, written by a teacher, presented as dialogue of teacher-student(s) interaction. In mathematics teacher education, lesson play has been used primarily with prospective teachers as a complement to traditional lesson planning. The LPE includes, in addition to a script for (part of) a lesson, observations of the actual taught lesson, and interviews with the teacher-playwriter in which the script and the lesson are discussed. We report on two rounds of one teacher LPE and the resulting modification. The investigation has shown that the LPE can be an effective tool for in-service teacher professional development.