Betty Bought Some Bitter Butter

James Naismith, invented a new indoor game, which could be played during the cold winter. He started work on it in December 1891. He wrote that he took some idea from other sports: when he was young, he played with his friends a game called "Duck on a Rock." In this game, one boy guarded his “duck” from the stones of the others; and the fun began as the boys gathered their stray shots. It was this game that was later to play such an important part in the origin of X.

Give me X.