Bounce a large ball up and down while your baby is watching. He will get better and better at following the bounce with eyes. Bounce the ball higher and lower, slower and faster. Baby will continue to practice tracking an object with his eyes and will be doing so with an object moving fairly quickly. He will also be learning the cause and effect of a ball hitting the floor and bouncing up as well as it coming back down and it also makes a sound every time the ball hits the floor.
Be sure to be happy, stop and clap, and generally have a great time interacting with your baby as you do this ball bounce stimulation activity.