A Wait stick. My students get very anxious and jump up and try to run up to the line even before i have called them. So to help reduce the pushing and shoving and the "I was sitting" being yelled out here is a wait stick. I used a large paint stick and attached velcro to it and then added the students pictures. Now the students can see whose turn is going to be next and when their turn will be. It is also is great because the special helper (this changes daily for me) can always be first.