I saw this in a second grade class on their last days of school. They called it the Power Test. You choose one helper to monitor the room, everyone stands and looks at the clock for one minute very still. It is supposed to help you gain your focus back and then you return to the activity. The monitor looks for anyone who talks or wiggles and they move to an area closer to the clock to do another minute. They were so serious about it!
The teachers table full of things to organize, clean and put away for summer.
Their "temporary desks" were black bags donated to put all the end of school papers in.