This is the programme I created on Scratch during this weeks ICT session.
For KS2 I would create a sheet with guidance to make the program for the whole or part of the ping pong game depending on ability.
As an extension I could ask the children to add to the programme by creating a scoring element. Every time the ball hits the black line, one point is taken away. But if the ball is hit back by the paddle, then one point is added to the score.