Device and method for occupying a human subject with physical and mental activities. Includes (a) human mountable and movable object (12) having total volume in a range of between about 0.5 and 5 cubic meters and being sufficiently strong to bear weight of a human subject (5) when mounted thereupon; (b) object motion control assembly (16, 18, 20, 22, 24) operatively connected to object (12), for controlling motion of object (12) when human subject (5) is mounted upon object (12); and (c) base assembly (30, 32) operatively connected to the object motion control assembly, for anchoring the object motion control assembly when human subject (5) is mounted upon object (5) and moving upon object (12) within a field of space determined by characteristics, configuration, and dimensions, of object (12), the object motion control assembly, base assembly (30), and behavior of human subject (5).