James "The Amazing" Randi, a personal hero of mine, debunks a phony psychic with telekinetic powers. Like Houdini, James Randi is a stage magician and skeptic/rationalist that devotes his efforts to exposing phony psychics by using his expertise as a performer and sleight of hand artist to figure out how so-called "mentalist," "medium" and "telekinetic" feats are done. James Randi also uses experiments to put claims to the test. One of my favorite recent ones is, he debunked the claim that more expensive connection cords improve picture quality.
What's the harm in psychics, after all? After all, they're not encouraging people to not get their children vaccinated, which is negligent and dangerous to the point of evil. They're not making outrageous claims about infinite petroleum under the earth and discouraging development of alternative energy. They're not stunting the understanding of children with fraudulent and untrue non-science like creationism.
The harm that psychics pose is that they blur the line between the real world and the untrue. Whether something makes good showmanship has nothing to do with whether it is true or not, and thus far, no one has been able to demonstrate under controlled conditions any ability to talk to the dead or move objects with their minds. When we go to see a romantic comedy, we enjoy it because we can understand that real-world romance isn't like that.
By the way, the claim that the heated lights together with the polystyrene created static electricity that prevented his mind power from operating? That's such transparent bullshit that it almost isn't worth debunking...but to flex my chemist muscles, here's why that couldn't be true:
Static electricity increases the colder it gets, not the hotter.
Why? Because the colder air is, the less humidity it stores. The more dry the air, the more likely there can be static. The factor that determines the amount of moisture that can be held at a temperature is called "Relative humidity." The RH, the capacity for air to be saturated with water, drops by 50% for every 10 degrees Celsius the temperature rises or drops.
(Incidentally, this tends to be how dehumidifiers work: by cooling air off. Sure, it works, which is more than I can say for some products, but it's hardly a mysterious process and is pretty much a glorified mini air conditioner. Egad, what mysterious process has taken place here? Sometimes, human stupidity is a bottomless pit.)