At first this sounds like a bad practical joke. Begin by turning the radio to a station playing static. Then lie down on the couch and tape a pair of halved ping-pong balls over your eyes. Within minutes, you should begin to experience a bizarre set of sensory distortions. Some people see horses prancing in the clouds, or hear the voice of a dead relative. It turns out that the mind is addicted to sensation, so that when there's little to sense - that's the purpose of the ping-pong balls and static - your brain ends up inventing it's own.
INCREDIBLE SHRINKING PAIN
Researchers at Oxford University announced the discovery of a powerful new painkiller: inverted binoculars. The scientists found thats subjects who looked at a wounded hand through the wrong end of the binoculars, making the hand appear smaller, felt significally less pain and even experienced decreased swelling. According to the researchers, this demonstrates that even basic bodily sensations such as pain are modulated by what we see. So next time you stub your toe or cut a finger, do yourself a favor: look away.
THE RUBBER HAND ILLUSION
If you happen to have a realistic-looking rubber arm in the closet, then this hallucination is for you. Begin by hiding your actual arm behind a box on a table so that you can't see it. Then arrange the fake arm on the table, so that from your point of view it looks like it could be your hidden arm
A friend should then stroke both the real hand and the rubber hand in the same place and at the same time. After a few minutes, you should feel like the fake limb has become your own flesh.
THE PINOCCHIO ILLUSION
This requires two chairs and a blindfold. The person wearing the blindfold should sit in the rear chair, staring at the back of the person sitting in front. The blindfolded person should then reach around and place one hand on the other person's nose. At the same time, he should put his other hand on his own nose, and begin gently-stroking both noses. After about a minute, more than 50 percent of subjects report that their nose feels incredibly long.
Jan Purkinje, a founding father of modern neuroscience, stumbled upon a reliable hallucination as a child. First he closed his eyes (very important), then tilted his head to face the sun and moved his hand quickly back and forth in front of his closed eyes. After a few seconds, Purkinje reported appearance of "beautiful figures," which gradually become more intricate.