For World Water Day, our agency decided to build an Arduino controlled closed system tap that uses a step motor to programmatically tighten a valve in the tap's plumbing as tweets with the hashtag #closethetap are posted to the Twitter streaming API.
We set 10,000 as the target for the valve to be completely closed. Check it out at www.closethetap.co.za
Nice! way to positively publicize your company's name , good one
Thanks 
The sponsor part is just a small addition at the bottom of the page. We'll enter creative awards so we're not that concerned with the publicity, but it's the FLOW (for the love of water) client we're hoping to help out. The Arduino experience was so fun for us, our first Arduino project. We'll definitely be thinking up awesome little ideas in the future!