Spirit boards are boards which have the letters of the alphabet, and other words and symbols on them. They are used to talk to spirits, using a planchette to spell out words. A planchette is a piece of wood on which each person trying to contact a spirit puts one finger. The planchette is supposed to move on it's own to spell out messages from the dead.
The best known spirit boards are Ouija boards, which are made and trademarked by Hasbro. A man named William Fuld named the Ouija board. According to Fuld, the word "Ouija" comes from the French and German words for "yes." this name is so well known, that most people simply refer to all spirit boards as Ouija boards. An author named Emily Grant Hutchings even wrote a novel using a Ouija board, in 1917. It is called Jap Herron: A Novel Written by the Ouija Board. She believed it was dictated by the late Mark Twain.
Can spirit boards really put you in contact with the dead? No one knows for sure. Some say the planchette is moved by spirits, but others say that the planchette is moved by the unconscious movements of the living players. Many people believe spirit boards can attract demons, and other evil spirits, and even lead to possession. Despite these warnings, spirit boards are still used in current times. Needless to say, their use should not be taken lightly.
For more on the spirit board's haunting history, see these sites: