This could be my next camera.
Here is what they have to say:
"I’ve always wanted to just be able to snap a picture whenever I wanted to, without having my friends freeze their smiles on their faces until the focus was complete. And now, that’s a possibility. The new Lytro pocket-sized cameras let you snap pictures whenever you want, letting you focus on whatever you want, later.
How it works, you wonder. Well, apparently the Lytro camera captures all the light rays flowing in its direction, an average of about 11 million, and captures the scene in “four dimensions”, unlike any other camera out there.
So, you, or someone else you share you picture with will be able to refocus and explore the entire scene from different vantage points after you’ve already taken the photo."
Here is an example to play with. Click on any part of the image to refocus.