I found a little hack to add sound to the Game 'PingPong' for the KIM-I
The original game was published in the First Book of KIM back in 1977.
The mod was added by George W. Hawkins a little later. Now I have the typical Pong sound when playing the game on the internal LCD.
Grab a copy here: https://github.com/netzherpes/Kim-Pong-with-Sound