Yes, I usually watch documentaries to learn more about a subject that I am interested in like an art movement, another religion, a political situation etc. I watch biographies quite a bit, and don't mind a history program that takes me far back in time.
The documentaries I like the most are DisneyNature. While I watch documentaries mostly as helpful research for me, these docs are entertainment foremost! I get really excited when a new DisneyNature title is released. I love animals, and love to experience the wild through Disney's beautiful and lush photography and enjoy their expressive and witty narrators like Tina Fey and Meryl Streep. I also love going to see their movies because it goes to a good cause. A percentage of the proceeeds get donated to wildlife conservation efforts.
My favorite installments in the Disney Nature series are Monkey Kingdom and African Cats. I was looking forward to seeing Elephants this year in theaters, and sad that I missed out on it this Earth Day.