Welcome to Science Buddies!
I guess the project that you looked at was this one:http://www.sciencebuddies.org/science-f ... p010.shtml
Here is another project from this site that involves basketball:http://www.sciencebuddies.org/science-f ... p021.shtml
If you're still looking for something different you can devise you own experiment. The first thing that comes to mind for me is how would a partially deflated ball affect game play?
You could time yourself and a few friends dribbling the ball up and down the court at maximum speed, and do this different amounts of air pressure in the ball. See if there is a pressure at which people can move the fastest. You would need an air pump that tells you the pressure in the ball as you are pumping it up.
Another thing you might measure is the how high the ball bounces when dropped from a fixed height at different air pressures. You could drop the ball from 10 feet in the
air every time on to pavement, and then measure the rebound height of the ball at different amounts of increasing air pressure.