An Inconvenient Truth.
An Inconvenient Truth won the Oscar for Best Documentary of 2006.
Smile Pinki.
The first Academy Award (Oscar) for Best Documentary was awarded in 1942.
Best Boy won the Oscar for Documentary - Feature - in 1979.
20 Feet from Stardom
The Lady in Number 6
She was the subject of the 2008 Oscar winning Short Documentary.
Undefeated won the Oscar for Best Documentary in 2012. The documentary focused on a high school football team in Georgia and had not been considered the top contender for the prize.
Marie Antoinette.
Contrary to popular belief, Nobel Prize winner Al Gore did not win an Oscar. He did go on stage when An Inconvenient Truth won the Oscar for Best Documentary. But the prize goes to the director of the movie. Gore was not the director of the movie.
The Beatles.
The 2015 Best Documentary - Feature Oscar went to Citizenfour.