Thanks to the ingenious ThinkGeek robot monkeys you can display the current wi-fi signal strength to yourself and everyone around you with this stylish Wi-Fi Detector Shirt. The glowing bars on the front of the shirt dynamically change as the surrounding wi-fi signal strength fluctuates. Finally you can get the attention you deserve as others bow to you as their reverential wi-fi god, while geeky chicks swoon at your presence.

Product Features:

• Glowing animated shirt dynamically displays the current wi-fi signal strength.
• Shows signal strength for 802.11b or 802.11g
• Black 100% Cotton T-Shirt
• Animated Decal is Removable (with hook and loop fasteners) for Easy Washing
• Battery Pack is Concealed in a Small Pocket Sewn Inside the Shirt
• Runs for hours off three AAA Batteries (not included)
  

Washing Instructions:

• Carefully peel animated decal from front of T-Shirt
• Unplug ribbon connector behind decal and remove decal
• Unplug battery pack and remove it
• You can leave the ribbon cable inside the shirt
• Machine wash gentle cycle on cold
• Hang to dry
• Please Note: If you plug the connector into the battery pack backwards the shirt will not animate properly. It will not damage the shirt. Simply reverse the connector.
  

From: http://www.thinkgeek.com/

I wonder how much radiation this shirt gets for detecting wi fi areas..hmmm..