‘Bottle Boys’ Play Amazing Version of ‘Billie Jean’

My kids used to be mesmerized by the way I could make sounds come out of a half-empty bottle.  I also consider myself pretty adept at making high pitched sounds from a straw.  

But, the group called the 'Bottle Boys' have taken this art to the next level.  I'm amazed at the music these guys can achieve, but I also wonder who had to drink all the beverages to get just the right sound.