I love documentaries. Here are a few suggestions I haven't seen made in the thread yet:
The Pruitt-Igoe Myth- a 2011 documentary film detailing the history of the Pruitt–Igoe public housing complex in St. Louis, Missouri, and the eventual decision to implode the entire complex in 1976. Really interesting.
Cobra Gypsies- stunning piece of work; beautifully-filmed. Filmmaker Raphael Treza traveled to northern India and lived among an ancient tribe known as the Kalbeliya for three months.
The Woman Who Wasn't There- This woman actually faked being in one of the twin towers in 9/11. Batshit crazy.
I Think We're Alone Now- People who stalk the singer Tiffany. Also file under 'batshit crazy'.
Black Tar Heroin- "An extraordinary look at two years in the lives of five young heroin addicts, Black Tar Heroin offers a rare and intimate portrait of how heroin devastates young lives." Filmed in the 90s, I think. Pretty interesting.
Thin- a documentary about an eating disorder clinic and the patients who go there. The film mostly revolves around four women with anorexia nervosa and/or bulimia and their struggles for recovery. Kind of sad. :(
The Interrupters- Members of the activist group CeaseFire work to curb violence in their Chicago neighborhoods by intervening in street fights and showing youths a better way to resolve conflicts.
Life 2.0- All about the magic that is Second Life.
Town of Runners- About kids from Ethiopia who want to run in the Olympics, and the difficulties they face.
Cropsey- SPOOKY! about child abductions in Staten Island, and the mental institution that used to be there.
just watched tonight: Web Junkie Chinese kids get sent to boot camp to overcome their internet addiction.
Some of these are on Netflix, some on Youtube, and the rest you can find on the documentary sites on Google.