This is a great video that has been going around the internet since its release a few weeks ago. I absolutely love vocal percussion and doing sound effects with the voice (Eric Whitacre has some nice choral pieces like that) and thought my readers would enjoy this piece as well. This group, the Pentatonix, does most (if not all) of their music a cappella (without instrumental accompaniment), and they include their own vocal percussion sounds. They’re pretty good!
I must note, however, that the girl does some very strange things with her mouth and voice and will probably have vocal problems later on in life if she continues to sing this way regularly. I do not advise copying her technique.