SitePoint and TechCrunch both have some information up about something that EffectiveUI is building for Intelligence Gaming. It's a video-based virtual reality training simulation for the army. It's one of the coolest RIAs that I've seen. The application uses a combination of high quality video and hardware to immerse people in the training environments. The hardware uses an accelerometer of sort so that when you move your head, the video moves with you. They've also done a lot to the audio processing so that as you move, the audio changes just like it would in a real situation.
When I was at the EffectiveUI offices in Denver I got to try the glasses on a check it out. It was one of the most fun things I've seen built on top of RIA technology. I'd love to see this become a wider trend. The combination of rich media power and easy interface design makes RIAs a perfect medium for this. As both Flash and Silverlight start to add more functionality around video processing and start to take advantage of the hardware more, we could see more scenarios like this enabled. Now we just need to make it easier to hook up to external devices.
There is a video that TechCrunch posted below.