This is a great drill – fun and very competitive. And because it involves only three players, everybody gets lot of touches.
It works this way: Two players receive serve on one side, one player serves on the other side. An ace earns the server a point. If the receiving team gets the ball back over the net with a pass, set, hit, the server needs to at least touch the ball to keep serving. A touch is a wash. If the server can dig to herself and set, she earns a point. A dig, set and kill earns her two points. Whenever the receiving team gets a side out, the players rotate.
As Austin Juniors Coach Mike Garcia describes here, the emphasis of this drill is on serving tough and playing good defense.