Our new Facebook contest has a winner. His name is Jeff Moyer of Gridley Paige fame and he knew right off the bat that this device is called a "capo" and it's used on a guitar.
How is it used? Specifically, Wikipedia describes the capo this way:
Musicians commonly use a capo to raise the pitch of a fretted instrument so they can play in a different key using the same fingerings as playing open (i.e., with