I first learned about Daniel Johnston when listening to an in-studio recording of Yo La Tengo covering his song "Speeding Motorcycle"; Johnston called into the studio and sang (or screeched, at times) the vocals. I didn't realize that he's an artist--and now one to be featured in this year's Whitney Biennial. The International Herald Tribune profiles Johnston, an artist whose "outsider" aesthetic and bipolar disorder would seem to belie his art education at Kent State, his affinity for Marcel Duchamp, or the inventiveness of his childlike drawings. Johnston lives at the home of his elderly parents after multiple hospitalizations and is the subject of the forthcoming documentary The Devil and Daniel Johnston" and appeared in POPaganda: The Art Crimes of Ron English (an artist mentioned here and here).
More: Rejected Unknown, the Daniel Johnston fan site, and Johnston's Wikipedia entry.