"Pitcher" stands about 15 feet away from the batter and throws a small frisbee or tennis ball can lid or any other type of plastic can lid toward the batter. You notice a difference in how the lid flies depending on which side is up when you toss. Change it up to increase the challenge to the batter. You can use regular bats, thundersticks, or speed bats.
Players seem to view these types of drills as "more fun" because it's not just the same old hit the ball routine. Plus these lids are not big and round like softballs, so they do encourage development of eye-hand coordination and the concept of watching the "ball" all the way because they are a bit more challenging to hit.