Hi Patricia: Interesting! I've done this exercise before and it is effective in breaking up tired "listening" lectures. It gets the students up and moving around, and probably help-0s get that old blood circulating, and it's just so unexpected that students do laugh and have fun with it. I've used that more when I need to mreingage students, not so much a back up plan. A good back-up plan should potentially be able to last the whole period - I don't think this activity would pass that test! Regards, Barry