I could spend all day showing links to GizMag, an emerging technology site that just has rapid-fire Cool Stuff, but this particular article is worthy of note.
Some bright lights figured out that if you put a computer controlled sail on a big ship, and combine it with a tracking/routing system that sets courses where there's prevailing winds, you can cut the ships fuel usage by 50%. Instead of just plowing along the ocean no matter what the conditions, using diesel fuel only, you can just be a little smarter and let the sail help pull the ship along.
"As the sail is spatially separated from the body of the ship the reduction of the ship's effective area by the system is economically insignificant. In its packed state the towing kite is easy to stow and takes up very little space. The existing crew is sufficient for the operation of the ship and the sail. Thus no additional staffing expenses are necessary."
It seems like such a simple idea, I'm boggled no one has thought of it before. They do mention that there were some tricks to overcome, like any tethered sail could cause the ship to heel over, but an active control system can limit that.