
Paintballs are essentially the "bullets" used in combat simulation games that use paintball guns. They are designed so that when they impact an opposing player they explode and leave a large splash of bright color at the impact point. Once a player has been "shot", they are considered dead and must leave the game.
The vast majority of the paintballs that are manufactured today are designed to be environmentally friendly. They are generally made from food coloring and gelatin, and since they are water-soluble, the paint can be easily removed from skin and clothing using nothing more than ordinary tap water. The down side to this is that if you play in the rain, it does get hard to determine who has been shot and who has not.
Paintballs can be purchased from any number of sources, both locally and over the Internet. The sport has become so popular nowadays that many mainstream sporting goods stores will carry a selection of paintballing equipment, including the guns and the balls. Furthermore, there are dozens of online websites that cater specifically to the modern paintballer, and many of these online sites are less expensive than a local store.