Ouija

Ouija is the belief that one can receive messages during a séance by the Ouija board (also called talking board, spirit board) and planchette. The fingers of the participants are placed on the planchette which then moves about a board covered with numbers, letters and symbols so as to spell out messages.
The term "Ouija" is derived from the French "oui" (for "yes") and the German/Dutch "ja" (also for "yes").

The motion of the planchette is explained by the ideomotor effect. A typical session with the board has two or more people touching the planchette with at least one hand each, so that no single person need apply much force in order for the group as a whole to cause it to move. Each person experiences the illusion that the planchette moves under its own power.