Aireal is a Disney Research/University of Illinois project that can generate the sensation of interacting with physical objects in thin air, by acoustically firing precisely aimed puffs of air:
In practice, Aireal can do anything from creating a button for you to touch in midair to crafting whole textures by pulsing its bubbles to mimic water, stone, and sand. This is all very neat, but maybe even more important, Aireal has an inherent convenience factor. A single Aireal could conceivably support multiple people, and a grid of Aireals could create extremely immersive rooms, creating sensations like a flock of birds flying by. And for the end user, taking part is never more complicated than standing somewhere. It’s capable of creating a virtual tactile environment without forcing everyone to strap on strange peripherals.
Disney’s Crazy Invention Lets You Feel Phantom Objects Floating In Air [Mark Wilson/Fast Company]
(via Beyond the Beyond)