Basketball was invented in 1891 by James Naismith, a gym teacher at the International Training School of the Young Men's Christian Association in Springfield, Massachusetts. Winter gets cold in Massachusetts, so Naismith wanted to devise an indoor activity that would keep his students busy and fit. Thinking back to rock-throwing games he'd played during his childhood in rural Ontario (origin of the phrase, "give me the rock"?), he nailed half-bushel peach baskets to both ends of the Springfield gym, split his 18-member class into two 9-member teams, and instructed the boys to try to toss a soccer ball (accurately, not forcefully) into the other team's goal.

It must have been an interesting game: 18 guys crammed onto a gym floor trying to dribble a soccer ball, then scrambling toward the rafters to retrieve the ball from the bottom-intact basket after each goal. Naismith quickly refined the game to its current form: two five-player teams, a ball four inches larger in circumference than a soccer ball, and hoops with nets and backboards.

With these modifications, the game took off. In January 1892 Naismith published the rules, including prohibitions against "holding, pushing, shouldering, striking, tackling, or tripping," in the training school paper. By 1896 the game had reached England, France, and Brazil; Australia, China, ...