Searching for Sugar Man (2012)

The best way into this list: two South African fans set out to learn what happened to Rodriguez, a mysterious 1970s Detroit singer-songwriter who meant far more to them than he ever did at home. Malik Bendjelloul shapes it like a detective story, so go in knowing as little as possible. It won the Academy Award for Best Documentary Feature, and it works even if you have never heard a Rodriguez song. Free with ads on YouTube's free movies.