The game room is described in chapter seven of The Westing Game.  It is big enough to fit eight card tables with two chairs each.  The walls are covered in sporting equipment ranging from ping pong paddles to bows and arrows.  Turtle notes that there is a full rack of billiard cues, meaning someone put away the one she armed herself with night before when following through with a dare.  There is also a chess board set up.  Theo notices one of the pieces has made the first move and so he sporadically plays with an unknown opponent.

Other descriptions of the house itself include the fact that it is chilly which shows it is probably large and drafty, as well as ornately decorated.  The chess game is described as having "finely carved pieces" (32).  Likely, the game room is as fancy and expensive looking as the rest of the house.