Daryl Davis is an African-American musician who, over the years, has backed artists ranging from Jerry Lee Lewis and Chuck Berry to Bo Diddley and Muddy Waters. But he has a very unusual hobby: He likes to seek out and introduce himself to members of the Ku Klux Klan, to give them an opportunity to get to know a black man. It’s an impressively high-risk, change-the-world-one-step-at-a-time hobby. Me, I collected stamps. Check local listings.