A New York City billboard ad sends an audio file right into the heads of people walking nearby.
The billboard uses technology manufactured by Holosonic that transmits an "audio spotlight" from a rooftop speaker so that the sound is contained within your cranium.
Alison Wilson was walking down Prince Street in SoHo last week when she heard a woman's voice right in her ear asking, "Who's there? Who's there?" She looked around to find no one in her immediate surroundings. Then the voice said, "It's not your imagination."
Imagine the possibilities for storytelling, augmented reality, for hacking, and so on.