A plastic gun, a LCD, a Gyromouse, mix, shake, here’s the VR Gun :

[youtube]http://www.youtube.com/watch?v=7Ym0tZSWGMc&feature=player_embedded[/youtube] [youtube]http://www.youtube.com/watch?v=cnGSpAZtm38[/youtube]

(I know, I’m two months late =)

You will only get the rotations from the Gyromouse, so walking won’t help you.

This is as clever as the R-Screen or the Virtual Showcase, but less complicated and cheaper =)