Solitaire is also a name of a game played with pegs and holes in the shape of a cross: perhaps the card game should be moved to Card Game, and an entry on Solitaire put here? Dave McKee -- Solitaire is also a game for one player, usually using pegs in holes. The board is in the following shape:
OOO OOO OOO OOOOOOOOO OOOOOOOOO OOOOOOOOO OOO OOO OOO
with a peg in each hole, except for the centre piece. Moves are made by jumping a piece over another piece, either horizontally or vertically into an empty hole, and the piece that was jumped over is removed from the board and the game. The piece that moved may move again in the same fashion.
The aim of the game is, ideally, to end up with a single piece in the centre hole in as few moves as possible, but ending up with only one piece left over, let alone in the middle, is still extremely challenging, and leaving a small number of pieces on the board is considered good going.