Abstract: Two playing boards with a matrix array of apertures are positioned so that one board only is displayed to each player. Electric circuitry including contacts are printed on one side of a flexible sheet which is folded so that contacts face each other adjacent each of the apertures. The circuitry is arranged so that the insertion of plugs into corresponding apertures of the two boards moves the contacts carried on the sheet towards each other to close a circuit energizing an audible signal generator.