Guts or guts disc (sometimes guts Frisbee in reference to the trademarked brand name) is a disc game inspired by dodgeball, involving teams throwing a flying disc (rather than balls) at members of the opposing team. One to five team members stand in a line facing the opposing team across the court, with the two teams lined up parallel to each other. Which team begins play is determined "flipping the disc", an action similar to a coin toss, but using the disc itself. One member of the team is then selected to start play.
That member then raises an arm to indicate readiness to throw, at which point the members of the opposing team freeze in position. The thrower then throws the disc as hard as possible at someone on the opposing team. If the thrower misses the "scoring area" (a demarcated area a bit larger than the space occupied by the opposing team), or if a member of the receiving team catches the disc, the receiving team scores a point. If the throw is within the scoring area and the receiving team fails to catch, or catches but drops the disc, the throwing team gets a point. The receiving team then picks up the disc and becomes the throwing team.
The receiving team must catch the disc cleanly in one hand, and may not move from position until after the disc leaves the hand of the thrower. The disc may not be trapped between the hand and any other part of the body, including the other hand. This frequently results in a challenging sequence of "tips", rebounds of the disc off of receivers' hands to slow the disc down, often involving multiple players on the receiving team.
Play continues until at least 21 points have been scored by one of the teams and there is a difference in score of at least 2 points.
source: Wikipedia
