When I have done this with my 10u team, they really enjoyed it. The drill works on bat speed and hand/eye coordination for all. This is a fun drill and a good drill to end a practice with.

Fun (Warm Weather) Hitting/Catching Drill
Water (at least a few 2 liter bottles worth)
Water balls (Qty 10-20 small and baseball sizes) – these are usually found at $1 stores in packs of 3 or 6.
Helmets – players should always wear a helmet when batting.
Bats – I prefer to use a heavier nerf bat for this.

Best to do in the outfield grass.
Fill the Water Bucket (at least 1/3 or more).
Place water balls in bucket of water next to the pitcher.
The coach pitches (about 10 feet distance) 10 – 20 water balls to batter.

The players line up 2-4 players on each side of pitcher and then the rest of team spreads out behind the pitcher and behind the front line of players. The batter hits the water ball (gets splashed) and a fielder has to catch it in the air.

The first one to catch the ball from each batter will be the next batter. The batter should hit a given number (5 -10) before becoming a fielder.

The fielders throw the ball they caught or tried to catch into the bucket so the pitcher can keep throwing pitches. The players just might throw a few at the Coach during this process (whoops).

After everyone has hit, we then play dodge ball with the water balls (keep bucket nearby to keep water balls soaked).

Tip to Coach: The coach usually ends up being the main target. My advice is to empty the water bucket right before the dodge ball game is over. Otherwise it might get dumped on you.