While I may not be big on outsider art, outsider music invariably makes me very happy. This might be because so much respectable, saleable pop music is so wretched and forgettable, and musicians who respond to that material in truly unconventional ways are so much less of a snooze. For an introduction, try author/producer Irwin Chusid's indispensible Songs in the Key of Z.
The first video below is Shooby on Showtime at the Apollo. The poor guy gets called "Scooby" just as he takes the stage, and gets booed off inside of about seven seconds. Must've been baffling and crushing for a performer who was a legend and a classic--in his own head, anyway. Below that is Lift Every Voice and Sing.
Just think what Shooby could've been in the present era of microfame and internet pseudo-celebrity. Truly a man ahead of his time.