I don't see why it has to do anything, but if you want to be 7800 compliant, you could use it as a pause for Pong. Make sure you toggle the pause only when then switch is toggled to black and white. Toggling back to color should NOT unpause the game.
Well what is the color/bw switch going to do then?
.....I guess the switch is not THAT important then. However it sounds like a screensaver is in order!!! Does anyone have any good ideas?