Undersea and in the air: VR offers a thrill a minute

v irtual reality in public entertainment has been called a zero-billion dollar industry. For three or four years, we've read and heard a lot of hype about the potential profits in taking VR technology developed for the military and using it to make people smile. But as yet only a handful of companies have attempted to create systems that can generate profits as well as graphics. Here's a look at some of the most successful ventures.