Freaks DVD (1932)
A classic of B-horror cinema, and a truly creepy tale starring many real-life circus freaks. Of course it's exploitational! How else can you get microcephalics in your movie? You'll be haunted by the chant of "One of us! One of us!" Or, you'll just repeat it in any halfway appropriate context...for the rest of your life.
this is a classic about side show performers. while the subjects of the film are treated with great humanity, it is impossible to watch this and not cringe.