Thanks to Paul Cornish on SLN for the tip off to this great Flash movie of Postcards of the Future.
Click the image below to see the movie (SWF format)If you need a blank postcard template (they work well printed on card), you can borrow mine from here.
Great work by Patrick Blower at Live Draw - check it out here.
Two more relevant ones in the archive:
Geo Engineering saves the World, and Ecotown