In the Denver Nuggets’ practice gym, a backpack was on the line. A designer backpack with a speaker built into it. An NBA star player’s backpack. Four of Jamal Murray’s high school friends and basketball teammates were visiting him in Denver. It was still early in his NBA career, and he was showing them his office. They had made plans to play pick-up together, like old times, so Murray upped the stakes by suggesting they play king of the court for the backpack. “Say less,” Josiah Riley told him. “I’m with it.” Standard rules. Rotating one-on-one matchups. If you get...