Slashdot ran a story today about a group of graphic designers who put together a realistic World War II D-Day invasion film. The original story is here. When Saving Private Ryan was filmed, it took upwards of 1000 extras to film this scene. These guys did it with 3.
They used green screens and staged pyrotechnics to create the various explosions, props, and other effects. In the end, the completed scene is incredibly realistic and lifelike. Incredible work for a small crew.
So, without further ado :