The charango is a small, rounded back guitar like instrument popular in the music of Peruvian Andes region. Kate Hathaway explains it all in the video below. Ms Hathaway forms half of a brother sister duo (the other half being James). You can learn more about this enterprising duo at their website and blog. They also have a number of videos on Youtube.
Update: This is a great song they wrote and play, called “Wait for Me,” being performed recently in a club in Peru:
