Fill up the bucket/container with water to the midline and drop in the Ping-Pong ball (you can use more than one ball, or different size plastic balls). Fill up the squirt bottle with water and let the child squeeze and squirt the water out into the bucket/container until the Ping-Pong ball falls out of the bucket/container.
This activity can be done with more than one child. The first child that has his/her Ping-Pong ball fall out of the bucket/container wins!
To work on developing visual motor skills, fill up the squirt bottle with shaving cream or foam and let the child squeeze the bottle to draw shapes and letters on a concrete surface or an easel.