Nice hack from the MIT Media Lab.
Most of the objects in your household have a very specific weight which remains unchanged for long periods. This weight, reckoned to several decimal points, can be used as a macro. For instance, your key ring's weight could be the macro for your Yahoo password. Or a stapler could indicate your Flickr photostream. To invoke a macro, all you do is place the tangible object on a USB-enabled electronic postal scale. (This one is $85 from Office Max.) The appropriate weight triggers the appropriate computer action. The experimental software, called Amphibian, runs on Windows only. The project is based in Hiroshi Ishii's Tangible Interface lab at MIT.