Coach or another player feeds ball across net. Other players are across net, ideally in a receiving position. They take turns calling out 'Short' or 'Deep' to predict where the ball will bounce. Any ball landing between the net and the service line is a 'Short' ball. Any ball landing between the service line and the baseline is a 'Deep' ball. Points are earned for each correct call. This game can easily be converted to a team activity.
Easiest: No rallies. Receiving players catch ball.
Harder: Players self-feed and play out the point, calling out 'Short' or 'Deep' for each ball as they play.