Hello Everyone
Can we play Ping Pong using ROS Turtlesim? Yes, now you can 
Here is a ROS weekly project done by Franz Pucher as the part of ROS Developer Learning Path-Course 1-ROS for Beginners.
Github: GitHub - fjp/ros-turtle-pong: Pong game for ROS turtlesim.
The next course: Mastering ROS will be starting next month and enrolling already started. Check it out from the following link