End-of-year student play days are frequently a tradition that provides elementary students an opportunity to be active in a fun, festive environment. Physical educators can use play days as a time to authentically assess their students while the students are enjoying the activities. Those planned by the students themselves have been found to be more successful. This article describes how a successful student-led play day, created and led by 5th grade students, was used to assess students based on the national and Wyoming Content Standards. (Contains 7 tables.)