One of the most impressive performances I've ever seen. http://www.youtube.com/watch?v=1qOQHB_V2g0
Bobby McFerrin, known best for his song 'Don't Worry, Be Happy', has a great range of musical ability, all of which he does with no instruments. From more popular music including his rendition of the Beatles' 'Blackbird' (http://www.youtube.com/watch?v=37DHXrFfwrE) to jazz and classical music such as 'Ave Maria' (https://www.youtube.com/watch?v=PgvJg7D6Qck), Bobby McFerrin needs no accompaniment to sound fantastic, and his arrangements and compilations of already existing songs are amazing (Watch his abbreviated version of the movie 'The Wizard of Oz' here: https://www.youtube.com/watch?v=u1mvfzoHm9g)
Interestingly, Bobby McFerrin no longer performs his most famous song 'Don't Worry, Be Happy' because it was used without his permission when George H. W. Bush used it in the 1988 presidential election. As an act of protest of this action, he decided to not perform the song anymore.