Dowsing is the action of a person called the dowser using a Y- or L-shaped twig or rod, stick or other device called a dowsing rod, dowsing stick, doodlebug (when used to locate oil) or divining rod to locate such things as underground water, hidden metal, buried treasure, oil, lost persons or golf balls, etc. Since dowsing is not based upon any known scientific or empirical laws or forces of nature, it should be considered a type of divination.

Dowsing rod
Dowsing is purported to be a psychic method of finding hidden things, i.e. water, gold, treasure, etc.
This use of Dowsing comes very close to the concept of using Ouija Boards for insight into the unknown, and quite frankly, it seems to us that a Ouija Board is much better suited for this type of inquiry.
http://www.crystalinks.com/dowsing.html
http://en.wikipedia.org/wiki/Dowsing