TeleSpy

With a built-in infrared motion sensor, this device available at Thinkgeek.com can call a pre-defined number in case of an intrusion. What's more, it can even allow you to listen to what is happening! Plugs into a standard telephone jack and can be considered to protect your home or eavesdrop into what happens behind your back, when you are not at home.

See through Glasses

A device by a company called Kaya Optics (http://www.kaya-optics.com) allows a person to see an X-ray vision through sunglasses, dark windows and even clothes. Can also be used to improve visibility and monitor pollution. More details available at the vendor's site.