Paintball is a sport where players compete to eliminate other players. The game is played indoors and outdoors as well as for competitions and tournaments. Several items are required: A marker (paintball gun), a loader (hopper), a compressed air tank, masks or goggles, and paintballs. Paintball Markers are manufactured by many companies and come in many shapes and sizes. Other equipment is available, like extra ammunition pods and paint grenades. Paintball can be played in empty fields,  with barriers to woods and even inside like room clearing. The general rule is you must have your mask on at all times on the field and if you get hit (a quarter sized paint mark) you are out. Paintball is often used in Law Enforcement and Military for practicing. Be sure to follow any rules for paintball in your area.