I doubt many of you have played this but its quite fun, when your winning :P
In real life, A is represented as if you were praying, B is represented as if you were developing a cross with your hands (its not religous game, im just trying my best to explain it lol), C is represented with both hands, palms facing downwards, and D is represented with both hands, palms facing upwards. Alright, so onto the game, basically, a caller, in this case would be the challenger of the duel (provoker) calls out a letter A B C or D, and makes the appropriate hand gesture, and all the other people (in this case just the person who is being dueled) try to at the same time do a hand gesture that is different from that of the caller, if they get the same hand gesture, or same letter, they get hit, if they both had A, then they get hit once, if they get B, they get hit twice, and so on, well obviously we cant hit over the internet so you just lose that many points, so if it was A, 1 point loss, B, 2 point loss, C 3 point loss, D 4 point loss, so initially there is no point wager, and if they DO get different hand gestures, its the other dueler (the one who did not calla letter) turn to call a letter, OR we could have it that the challenger loses points based on the other duelers hand gesture...
its just an idea, if you want a better explanation alex, there is always msn!