For the Gamer Who Has Everything: VirtuSphere
"The device consists of a large hollow sphere, which is placed on a special platform that allows the sphere to rotate in any direction as the user walks within the sphere.
The user enters the sphere with a head mounted display, which permits virtual vision in any direction. As the user moves, the sensors under the sphere transmit information about the users speed and direction to the computer. The user looks at the head mounted display and sees a virtual three dimensional space which is generated by the computer in response to his-or-her movements. The user can interact with objects in virtual space with the help of a special manipulator."
Perfect! Great! Now all I need to try it out is a room with a 9-foot tall ceiling, and, well, a spare hundred thousand dollars ($100,000).
Maybe if I added a paypal donation link?