A couple of weeks ago my secret sender sent me an email with a link to the following site.
The purpose is to help Water Aide "demand the end of the struggle for the 1.1 billion people who do not have access to safe water." Check out the website but all that is required from you is to knit a 15x15cm blue square and send it to the address in London, England. Seems easy enough. I have some blue yarn left over from my first hat projects from a few years back and plan to knit up my contribution tonight.