Some good ones I've seen lately:
The Jinx - The Robert Durst murders, extremely fascinating and just goes to show you that if you have enough money, you can do whatever the fuck you want, even kill people, chop up their bodies, claim self defense, and dump them in the ocean and get away with it.
Merchants of Doubt - an excellent look into the disinformation tactics of big tobacco, fossil fuel companies, and climate change deniers. Really opens your eyes to how much bullshit is being spewed to the public.
That Sugar Film - an Australian guy, after being completely off sugar intake in his diet for 2 years, goes on a 60 day diet taking in the average daily consumption of sugar like most other Australians. He goes from being in the top 10% of healthy males of his age, to the bottom 20% in 2 months, becomes pre-diabetic and develops fatty liver disease, all by eating so called low fat "health foods".
Montage of Heck - an intimate look into the life of Kurt Cobain and his cunt of a wife Courtney, lots of home movies and personal recordings of Kurt.
Soaked in Bleach - a look into the murder of Kurt Cobain and the allegations of the PI that was hired by his wife that she had him killed. Not sure what to think about it, but it was interesting nonetheless.