This story has been making the rounds in the news lately,
Courtesy Wikimedia Commonsdescribing a study in which a computer reconstructed video clips that subjects viewed. Participants in the experiment watched video clips while their brain activity was monitored by fMRI. Then the computer selected from millions of YouTube clips it had "seen" to make a composite video clip, some of which look eerily similar to the original videos that the participants watched.
No need to break out the tin foil hat just yet. Volunteers for this study had to lie motionless for hours for their brain activity to be scanned. But this technology could easily lead to systems of communication that aid patients whose normal channels of communication have broken down because they are paralyzed or even comatose. If you're interested, you can see the original paper here (subscription required). Take a look at some sample video from the study: