Try this: Cell Phone Faraday Cage

Try this:

You will need two cell phones, or a cell phone and a land line, and a large piece of aluminum foil. First call one cell phone from the other phone, just to make sure everything is working properly. Next, wrap that cell phone in the aluminum foil, completely enclosing it. Now, call the enclosed cell phone. Write me a comment and tell me what happened!!!

If you did this correctly, you created a Faraday cage around your phone. Here's how it works. As you might remember, cell phones work by receiving radio waves, a type of electromagnetic radiation. Picture a radio wave in your head. Picture a cage in your head. Now, imagine that the mesh in the cage is sooooo teeny that the radio waves cannot fit through the mesh of the cage. The cell phone can't send any signals out, and it can't pick up any coming in. To summarize in more technical language: A Faraday cage will shield an object inside of it from the effects of electromagnetic radiation as long as the microscopic holes in the cage are smaller than the wavelength of the radiation.

To learn more about Michael Faraday or Faraday cages, you could start with Wikipedia. To see something really cool about how Fraday cages are applied, click this link: http://www.glumbert.com/media/highpower
Would you want this guy's job?