On a Sunday evening in late February 2012, I gathered around the TV with my family in Los Angeles to watch the NBA All-Star Game. In Sanford, Florida, a continent away, a teenage boy named Trayvon Martin was also getting ready to watch the game, and like most 17-year-olds, he wanted some snacks for the matchup. He put on a hoodie and headed to the convenience store for a pack of Skittles and a can of Arizona Iced Tea