One of the most popular ones was this one by Ariel Garten, CEO of Interaxon presented at LeWeb2010. You can watch her speech "Thought Controlled Computing" here:
Yes, we were sitting there in the audience watching her brain wave while she talks ;)
What about the Japanese usage of brain waves? There's a bunch of interesting installations, but I'll introduce a cute one here - "Necomimi" by Neurowear project. You wear cat's ear shaped device which would lay down if you are relaxed, stick up if you are concentrated.
Looks like I was concentrated when I tried it this time ;)
Disclaimer: The opinions expressed here are my own, and do not reflect those of my employer.
