Source: Wikipedia, "Doctor Pong", available under the CC-BY-SA License.
Doctor Pong, also known as "Puppy Pong" was an adaption of the original arcade Pong for use in a non-coin-operated environment. It was conceptualized by Nolan Bushnell, Steve Bristow, and a marketing firm to move their arcade games in to a non-arcade environment - in this case to help occupy children in pediatricians’ waiting rooms. Originally designed to be model of Snoopy's dog house with Pong built in to the side of it, when Charles Schulz declined Atari the use of Snoopy, the model was changed to a generic doghouse with a puppy looking over the top. Puppy Pong saw a limited production run and was in testing stage at Chuck E. Cheese's early locations.