Arena football is a variety of indoor gridiron football played by the Arena Football League (AFL) and China Arena Football League (CAFL). The game is played indoors on a smaller field than American or Canadian outdoor football, resulting in a faster and higher-scoring game. The sport was invented in 1981, and patented in 1987, by James F. Foster, Jr., a former executive of the National Football League and the United States Football League. It was a proprietary game (the rights to which were owned by Gridiron Enterprises) until 2007, when the patent expired. Though not the only variant of indoor American football, it is the most widely known, and the one on which most other forms of modern indoor football are at least partially based. - Source: Wikipedia
