An oldie but a goodie as far as movie promotions go and personally one of my favorites. When it promotes something that is intended itself to be scary, it can be, prankvertising can definitely be irresistible.
Thinkmodo, a digital media agency, is getting rather good at public horror-movie stunts. First, it got a creepy chick to literally bend over backwards in a beauty salon for The Last Exorcism Part II. Now, it gets another creepy chick to show off freaky telekinetic superpowers in a coffee shop for Carrie—the upcoming horror film based on Stephen King's 1974 novel.
The looks on the patrons' faces are priceless. (For a change, it's not difficult to imagine these are real people, rather than actors.) Not insignificantly, the stunt ties seamlessly into the product, too—terrifying people also happens to be the point of the movie.