"Don't drop the baby" is a great drill for training court vision and communication with teammates. Coach Emily Hiza explains it here, then runs it with her team. The drill is 3 vs. 3. At any one point during play, 2 of the 3 players on each side are holding a volleyball while the third is playing the "live" ball. Once the player who isn't holding the ball plays the "live" ball, the player who will play the ball next tosses the ball she is holding to the player who just played it.
Lots of concentration is required, and it's a fun challenge for teammates to work together to score points without "dropping the baby."