For eons we've wondered what it would be like to walk around in a bona fide Virtusphere, and at GDC last week we finally got our chance. The large plastic cage can turn and roll in any direction, and once replete with a wireless head-mounted display and fake gun, we were ready to take on some polygonal alien baddies. Getting into the cage is surprisingly easy, but unfortunately once we had a screen strapped to our head our well-honed sense of balance was right out the window, and we found ourselves staggering around a bit as we got used to the motion of the cage. The real military versions have a motion sensing gun controller, but we