After a little arm-twisting, I convinced dad we could finish planting wheat the next day so we could watch.

Summit Series: Canada versus USSR, first time using pro NHL players.  From wikipedia:

The first four games of the series were held in Canada and the final four in Moscow. The Soviet Union surprised the Canadian team and most of the hockey media with an opening game victory, 7–3. Many sportswriters had predicted an overwhelming victory for Canada in the series. Canada won the next game 4–1; the third game was a tie and the Soviets won game four to take a two games to one lead after the Canadian segment. The series resumed two weeks later in Moscow. The Soviets won game five to take a three games to one series lead. The Canadians won the final three games in Moscow to win the series four games to three, with one tie. The final game was won in dramatic fashion, with the Canadians overcoming a two-goal Soviet lead after two periods. The Canadians scored three in the third, the final one scored with 34 seconds left, by Paul Henderson.