Fog Screen Technology

Looking to change projection technology as we know it the FogScreen® projection system, produces a thin curtain of “dry” fog that acts as a translucent projection screen, allowing it to display images just about anywhere. Using simple tap water and digital projection technology the images FogScreen produces literally float in midair, allowing users to touch or walk right through the "screen." This technology is quickly becoming adopted among those who aim to impress at tradeshows, casinos, nightclubs, museums etc.

source: http://www.fogscreen.com/en/