The DIY mavens at Evil Mad Scientist Laboratories made this tabletop playable Pong game and very thoroughly documented the build and functionality.

What is PONG supposed to represent?

Our answer to this question is a game somewhere between pinball and ping pong: Two players each have a single knob that controls the position of a paddle along a short track. Using the paddles, they bounce the ball back and forth and try not to miss the ball, lest the other player score a point. The paddle surfaces are curved, so that the ball reflects in different directions depending on the position of impact. The paddles are powered, so that the ball keeps a fairly constant velocity between the two sides, and the speed gradually increases as the game is played. The playfield is level and has a dotted line down the middle, and the scores are displayed on either side of that line. There are top and bottom walls of the playfield that the ball can bounce off of. Sounds possible, right? So we built it.