Well, This is topic that, After looking at the Pong video, Striked me a inspiration for this topic of ideas for "Games" Out of bricks,Good ideas get to be shown in this post.
For example, Let me show you my idea..
TRON "lightcycles"This seems possible.The game works like this game made with java,
http://www.nubis.com/tron/tron.htmlYou have a black wall out of 1x1, Color in the edges and make it the "Collision" For the cycles, Make a dot and make it able to move around the wall (Like the dots in the pong video) Make it so that it leaves behind a wall after itself that is the "Collision" Too, Add another dot (Any color) and make another control pad for it, And there you go! :D