According to a well-respected and apparently not crazy British scientist, Hurricane Sandy could have been completely suppressed if only we'd tossed a bunch of old car tires into the ocean ahead of time. Oops.
The scientist in question is Stephen Salter, Emeritus Professor of Engineering Design at Edinburgh University. His idea involves stopping hurricanes dead in their tracks by robbing them of the energy that they need to keep going, using a contraption called a Salter Sink that's made largely of spare car tires. Here's a cross section:
Basically, a Salter Sink is just a big plastic ring (anywhere from 10 to 100 meters in diameter) filled with car tires for flotation, with a plastic tube in the center that extends down maybe a hundred meters or so into the water column. And that's it.
The way it would work is that waves would wash over the top of the ring, leaving warm water from the ocean's surface inside as they pass. With each successive wave, that warm water gets pushed down the tube and out the bottom, where it mixes with much colder water down below, effectively turning the Salter Sink into a giant heat pump. A single large Salter Sink can transfer something like 10 billion watts of heat away from the ocean's surface, and it's that heat that provides the power for hurricanes. With enough of these things (like, hundreds or thousands) floating around in hurricane formation areas, there simply wouldn't be enough available energy for storm formation anymore.
Here's a video of how the Salter Sink would work:
As you can see, it's made completely of cheap materials, and it's totally self-powered from wave energy, but it still manages to transfer a huge amount of heat away from the surface. The Salter Sink concept is now owned by Intellectual Ventures, and while more research needs to be done to assess potential environmental impacts, it seems like the amount of money (and lives) that could be saved by giving these things a shot would be well worth the effort.