Carrotmob Makes it Rain... Environmentally
Meant to this a while back from an email that went round at work.
Love the idea. Simply... Offer to bring in a whack of business for one day to one business if they'll pay for environmental improvements to their business with the proceeds.
Seems like the first run went well (and you have to love the Lil Wayne video spoof). Have to see whether it's sustainable, but it is an interesting idea in crowdsourcing.
(thanks to Anu K. for the link)