I modded my atari2600 so that you can use the second joystick as a select and reset switch.
It's a really cheap mod and not very complicated. If you don't want to drill holes in your atari2600 you can just lead the wires out of the back of the console and have an external switch.
I came up with this while playing asteriods. I used an extention cable to be able to play from the couch, but every time I died I had to walk up to the console and reset it. You can turn the mod on and off with a switch, so you can still play with two players, but then the loser has to reset it :-D
