Yet another sport we can adapt to our own nefarious purposes! Actually we are just borrowing the
If you are not familiar with volleyball, here's what we are doing differently: in volleyball, you cannot earn a point unless your team is the serving team. So have your students play singles or doubles, but allow them to earn points only if they are the ones who served that point. If they served but the other team won the point, serve transfers to the side that won the point. Try first to X points the first time you do this to avoid confusion. Once they get used to the idea, you can return to traditional tennis scoring but make sure everyone is paying close attention to the score.