You can make someone hallucinate with only a ping pong, a red light, and a radio!

A ganzfeld experiment is a technique used in the field of parapsychology to test individuals for extrasensory perception.

It uses homogeneous and unpatterned sensory stimulation to produce the ganzfeld effect, an effect similar to sensory deprivation.

In a typical ganzfeld experiment, a "receiver" is placed in a room relaxing in a comfortable chair with halved ping-pong balls over the eyes, having a red light shone on them. The receiver also wears a set of headphones through which white or pink noise (static) is played.

The receiver is in this state of mild sensory deprivation for half an hour. During this time, a "sender" observes a randomly chosen target and tries to mentally send this information to the receiver. The receiver speaks out loud during the thirty minutes, describing what he or she can see.