Okay, this is weird (via Tris). It turns out that if you peel Scotch tape in a vacuum, the action generates small but significant amounts of X-ray radiation—enough, for example, to make an X-ray image of a finger.
Keep in mind that this only happens in a vacuum, so your everyday uses of Scotch tape—in the air, in other words—pose no danger. But it is pretty bizarre, and something the Soviets apparently figured out more than 50 years ago. Some speculate that the phenomenon could lead to portable, battery-free X-ray machines powered by hand cranks or other muscle power for use in developing countries. Neat.