April 20, or 4/20, is a day when many people across the world celebrate marijuana culture by toking up, jamming out to tunes and filling up on munchies. But the American Civil Liberties Union (ACLU) is using the unofficial cannabis holiday to draw attention to a serious issue: Despite the growing number of states that are enacting legalization laws, people of color are still much more likely to be arrested for marijuana than white people are—even though consumption rates are virtually identical across races.