You'll stop the rain.
An exhibit at London's Barbican art gallery by Random International allows visitors to walk through an indoor rainstorm without getting wet. Sensors determine where your body is moving within the pouring rain and shut off the water, allowing you to remain dry.
The creators look at it as both art and as a social experiment - how will people react when they approach the water?
The Rain Room
Another good video, from the BBC:
Barbican's Rain Room where visitors stay dry, BBC>>
Found via Kottke>>