Bob Perilla is the leader and founder of Big Hillbilly Bluegrass, a band that performs regularly at venues in the D.C. area and other parts of the country. The group has also been tapped by the State Department to travel all over the world in the role of cultural ambassadors. Their month-long tours include stops in many countries of central Asia. The group will perform a free concert at the Kennedy Center in D.C. on Dec. 19.

What is bluegrass music?