Of course, having everything attached to a chassis of some sort is much easier than mucking about with loose components. Here are some pictures:

The three tubes to the left generate horizontal and vertical sync signals and amplify the video signal. The four to the right generate an object on the screen, which can be positioned with the two pots to the right of the chassis.

There will be four objects in total: Two paddles, the ball and the playing field. The ball is logically compared to the playing field; if it falls outside the field vertically, its vertical direction is changed. If it hits a horizontal edge a point is awarded to the other player. If the ball hits a paddle, the horizontal direction of the ball is changed. The spaces that haven't been completely drilled out will be used for game logic (bistable flip-flops etc). I didn't drill them out because my drill battery went flat...