Jim Foster, a promotions manager with the National Football League, conceived of indoor football while watching an indoor soccer match at Madison Square Garden in <answer>1981</answer>. While at the game, he wrote his idea on a 9x12 envelope, with sketches of the field and notes on gameplay. He presented the idea to a few friends at the NFL offices, where he received praise and encouragement for his concept. After solidifying the rules and a business plan, and supplemented with sketches by a professional artist, Foster presented his idea to various television networks. He reached an agreement with NBC for a "test game".
In what year did Jim Foster conceive of the idea of arena football?
1981