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: https://github.com/fjp/ros-turtle-pong
The next course: Mastering ROS will be starting next month and enrolling already started. Check it out from the following link