Listening in on the neighbors is always way too tempting to resist. If your walls are just a little too thick, you can pick up this handy gadget to help you out. Instead of trying the usual trick of pressing a glass against the wall, you could have an actual gadget do the job. Plus, this is far more portable than carrying around a glass. Although keep in mind, the seller does warn that some countries do actually prohibit the ownership of spy devices. Which makes it seem all the more awesome.
The device has an earphone jack to make it possible to listen. It also has an on/off switch, a volume dial and a built-in rechargeable battery. It will work on doors, windows, steel plates, walls and more. To use it, just press the metal device up against the wall and listen in through your earphones.