In 2009 TED conference , MIT researcher Pranav Mistry has demonstrated Sixth Sense Technology. With this technology, we can interact with the computer through our fingers.
Sixth Sense is an attractive technology, and its total hardware costing is under $350 and all the software will be an open source.
Just imagine, if this technology could integrate in iPad... then, all the workings may be done in a screen floating on the mid-air.
A Los Angeles film student Zach King, with his video editor, created a neat video showing iPad screen floating in the mid-air and he is interacting with it very easily. He did a great Job! Lets wait for the Future- And it is Not at all impossible.