Split court doubles is a good way to maximize space in a gym. Two games can be played at a time on a single court, which is divided in half the long way using an antenna or a foam noodle.
Coaches can tweak this game to fit the level of play or to address certain criteria. For beginning and low intermediate players, you may want to have players initiate play by "bowling" the ball over the net. With more advanced players, play can begin with a serve.