Keep the door to the room open whenever possible, using a door stop to secure the door if necessary.
Open windows in nearby rooms so that some natural, fresh air is able to make its way into the room. Place an electrical fan in the hallway to direct the fresh air into the room.
Install a ceiling fan in the window-less room and keep it running as often as possible. It will keep the air in the upper half of the room circulating.
Place two or more electric fans in the room to keep the air in the lower half of the room circulating.