James Randi, a.k.a. The Amazing Randi, magician and author of numerous works skeptical of paranormal, supernatural, and pseudoscientific claims has for about ten years offered “a one-million-dollar prize to anyone who can show, under proper observing conditions, evidence of any paranormal, supernatural, or occult power.” His rules were little more than what any reasonable scientist would require. If you are a mental spoon bender, you couldn’t use your own spoons. If you claimed to see auras, you’d have to do so under controlled conditions. If you claimed to be able to do remote viewing, you wouldn’t be given credit for coming close in some vague way. If you were going to demonstrate dowsing powers, you would have to be prepared to be tested under controlled conditions. If you were going to do psychic surgery or experience the stigmata, you would have to do so with cameras watching your every move.
Here is a video clip of Randi exposing Geller and Popoff from NOVA’s “Secrets of the Psychics”: