Well here's a website you can use:
http://en.wikipedia.org/wiki/Dodge-ball
http://dictionary.factmonster.com/dodge-ball
Here's some of my information:
There are multiple ways of playing dodge-ball. The way I am about to explain also can be called wall-ball. But is still a type of dodge-ball. One person who is it has to use the dodge-ball to hit the other players who are standing backed up against a wall. You should use at least four total players if you want it to be fun. The person who is it is backed up usually atleast 5 yards from the wall. After he hits somebody with the dodge-ball, that player is out of the game. If it is a head-shot, it will not count. The main objective for the players on the wall is to either keep dodging the ball or catch it. If they catch it, they take the place of the person who was just throwing the ball. After everybody is out besides one person, they have one chance to catch or dodge the ball. If they succeed in either one of these, they are it. Note: If the ball hits the ground or bounces off the wall and hits somebody, it does not count.