"I started playing pickleball more than 50 years ago," Bill Gates says in a new video — not long after the game was invented...

The 66-year-old Microsoft co- founder wrote in a post that he was surprised by the sudden popularity of one of his favorites. It has become America's fastest-growing sport because it has been confined to the Pacific Northwest for decades. It is a mixture of tennis, badminton, and ping-pong. I expect you to hear about it soon. The sport began in 1965, because of boredom. One summer evening, three dads came home from work and found their children complaining that there wasn't anything for them to do. They found a net, a Wiffle ball, some ping-pong paddles, and created a game that the entire family could play. The three friends worked together to create a set of rules, codify the court layout, and introduce a larger plywood paddle that was good for hitting the ball. They called it pickleball. Word began to spread in Seattle. The game's inventors were friends with my dad's friends, including a state legislator and a lieutenant governor. He was inspired to build a pickleball court after learning about their invention. Since then, I've been playing a lot. The community was very small. I don't think there was a lot of people in the Seattle area who had ever watched the sport. I don't think anyone expected it to go national. Over the last two years there has been a 40 percent increase in the number of players. It will only get bigger. It's the best thing about the game. I look forward to playing the game with my friends and family more often during the summer.