I have invented a new game. You will need:
-2 zappers (pref. one orange, one grey)
-2 duck hunt carts (or any combo cart that has duck hunt on it)
You thought you were good at Duck Hunt? You were so good you could play with either hand and still shoot all of them? You can clay shoot a single pixel? You're completely bored of Duck Hunt? Well, you haven't played DOUBLE DUCK HUNT!
Try to get two zappers of a different colour so that you aren't confused. Start a game of Duck Hunt on both TVs. Try two ducks on each screen if you're feeling especially adventurous/cocky. NOW GO!
Ok, you still think you're a good shot? Move back from the TV. Try clay shooting on one screen and duck hunting on the other. Mmm, sensory overload!
This is a great use for free TVs from the classified ads. They don't need to be good, or new, they just need to be able to resolve Duck Hunt to an OK degree. Then you can shoot them for real afterwards if you want to feel really pro. Just make sure you have parental approval and are following all the firearm restrictions in your area.