A plurality of magnetized game pieces are inserted one by one in a piece holder frame of nonmagnetic material along a piece guide formed therein. In the row of game pieces, two adjacent pieces are held in contact with or spaced apart from each other under magnetic attraction or repulsion acting therebetween and the row length is variable and unpredictable. The piece holder frame may be formed with any desired number of piece guides in the form of a blind piece-insertion hole or an upstanding post. The game pieces may be permanent bar magnets themselves or take a composite form including a body portion of nonmagnetic material and one or more magnet pieces embedded in the body portion at each and thereof. To make the game further changeful, the game pieces may each be divided into two axial half sections which are joined together for relative rotation to enable reversion of its polarity.