Adding to my project from last week, I tried to give it a purpose and thought that it could be turned into a game in which you step on the semi-cylinder to make the ball jump and land on the aluminium foil on the other side of the box. I have used the Arduino to make the LED light up if the tennis ball touches the aluminium foil exactly and stay lit until the ball slides back down and touches the foil at the starting point.
Here is the code that I used: https://gist.github.com/yhk343/91b72544f0e0a46444641a15c4de6d88