Abstract: A portable wall board system is provided for enclosing a playing area such as a roller hockey rink. The wall board system includes panels and supports having corresponding keys and keyways that interlock to form a continuous inner wall for the playing surface. The system further includes doors that interlock with the supports at desired locations. The supports are hollow in order to receive a ballast material such as water. The invention also provides a method for enclosing a playing area using the above elements.