The song is Such Great Heights, originally written and recorded by pop group The Postal Service in 2003. This one has become entrenched within the pop culture through being included in the soundtrack of several popular television program, a number of commercials, and more than a dozen covers by other acts.
Joy Kills Sorrow uses it to demonstrate their particular skill for applying the instruments and techniques of bluegrass music to material from outside that realm, both original and cover songs.
The video was filmed and produced by fellow-Bostonian, Andy Cambria.
Look for Joy Kills Sorrow touring in Pennsylvania, Virginia and Tennessee next month, following a show this weekend at the Summerfolk Music and Crafts Festival in Ontario.