Love this idea ~ The Tappening Movement is an educational campaign to move people away from bottled water. A clever devise they created was this "Start a Lie" website in which you choose from a number of witty, implausible lies about bottled water such as "Bottle water hates Father of the Bride" and "The US Government uses bottled waterboarding" and then spread the word on email, Facebook, Twitter or Digg (what no FriendFeed??) It's not a non profit, but it is quite clever.
