Guitar as vehicle for a good cause: The 1 Blue String campaign seeks to raise awareness about a common, but hidden problem. According to their site, 1 Blue String:

(A)sks guitarists to replace 1 of their 6 guitar strings with a free blue guitar string, to symbolize the the 1 in 6 men who dealt with some form of sexual abuse in childhood.

Find out much more at the official site.

Right here.