Flag football is a version of American or Canadian football. The rules are not very different to those of the regular game. Instead of tackling players to the ground, the other team must pull a flag or flag belt off of the player carrying the ball. Flag football is a game played with no padding. Full contact is not allowed. The first game of flag football was played in the 1930s. It was later played on military bases in the 1940s as a game for the military.