GPS Satellite

Given its widespread commercial use in everything from cellphones to cars, it's easy to forget that the global positioning system was created as a military application, and the satellites that it depends on are still owned and operated by the U.S. government. In case you need a reminder, President Bush has furnished one, in the form of a plan to shut the whole GPS system down in the event of a national crisis in order to prevent its use by terrorists. The White House has also ordered the Pentagon to put together a plan to block overseas GPS access selectively during military operations, and apply similar jamming to non-U.S. systems, such as the EU's forthcoming Galileo program.  Though administration officials insist that a shutdown would happen under only the most extreme circumstances, you may want to brush up on your map and compass-reading skills and memorize some escape routes if you've become wholly dependent on your Navman for getting around.

DIY Headphone Beanie