Is it a plant? is it a greenhouse? No, it's a breathing, green car. You heard it right, General Motors has designed a photosynthetic car called, brilliantly, the Hummer O2.

Designed, mind you. Not created. They envisage that, were it to ever see the light of day (oops - a pun), the Hummer 02 would "breathe" through algae-filled body panels that would transform carbon dioxide into oxygen and release the gas back into the environment.

It sounds to me like they're going to have algae coming out of their ears as it grows and grows. And frankly, they're kidding themselves if they think that taking algae from the sea and making it grow on in transparent cars is going to save the planet. But hey, you can't fault them for being creative. And they won the 2007 Los Angeles Auto Show Design Challenge for their pains. There's more info and some great graphics here.