Today I happened upon this delightful video from, oddly, the World Science Festival 2009:
World Science Festival 2009: Bobby McFerrin Demonstrates the Power of the Pentatonic Scale from World Science Festival on Vimeo.
While I expect he’s made a great deal of money off of “Don’t Worry, Be Happy”, it’s unfortunate that that’s what most people think of when they hear McFerrin’s name. I don’t know much about jazz, but every time I hear him he strikes me as this remarkably capable and original vocalist.
DarrenBarefoot.com 
For some deep limbic reason, big massed groups of singers like that bring me close to crying. I speculate about why in my own post.
The guy is incredible… look up CIRCLE SONG. There are so many actually. Check out his vocal version of “Flight of the Bumblebee”