Until now, when I thought of barbershop style vocal music, I thought of four guys standing still and working some really tight harmonies. Take a look at this video from the 2009 International Barbershop championship, featuring the winners in the chorus division, the Ambassadors of Harmony. Incredible harmonies and movement.
For more on this competition, see this article by Robert Elisberg at Huffpo.
Wow. Just wow.
Not to mention, these guys are from St. Charles, MO. Great job, AOH!