The kids wore running numbers just for fun. This is Part 2 of a series to help people design school running programs.
Recess is popular for mileage programs.
You have a captive audience. Some clubs meet before or after school, or alternate between these periods on different days. Other schools incorporate their running into the school day. In any event, do what is best for your school population and stick to the schedule. Work with the school administration on a permission form.