Airplane
One volunteer is designated air traffic controller and the other is designated the airplane. The airplane is instructed to close her eyes. The players milling about now become the terrain between the air traffic controller and the airplane. The terrain should be passable. Players can clump together to make terrain that make require the plane to crawl under. The air traffic controller guides the slowly moving airplane (player with her eyes closed) by giving verbal commands. An improvised radio voice is a nice touch