EEG for the Wii and in your basement
There's a company, Emotiv, that's building an EEG interface for the game systems. Any company with a science-fiction-y vision statement sounds like a good time to me:
Communication between man and machine has always been limited to conscious interaction, with non-conscious communication -- expression, intuition, perception -- reserved solely for the human realm. At Emotiv, we believe that future communication between man and machine will not only be limited to the conscious communication that exists today, but non-conscious communication will play a significant part.
Our mission is to create the ultimate interface for the next-generation of man-machine interaction, by evolving the interaction between human beings and electronic devices beyond the limits of conscious interface. Emotiv is creating technologies that allow machines to take both conscious and non-conscious inputs directly from your mind.
They even have a cyborg-looking woman on the page.
Their claim is to detect emotion states of the player. Do you really need EEG for that? What about something less sexy like skin conductance? Facial expressions or more? I guess a big metal helmet detecting your brain must be inherently fun.
Along similar lines, the Internet has lots of advice on homemade EEG, with impressively detailed how-to instructions. Other sites seem to focus less on reading your brain's outputs, and more on modifying its state/signals. For example, apparently you can hack your brain with an iPod. Sign me up, what I've always wanted.
(To be fair, here's a more complete page on entrainment. The Emotiv link is from folks at neurodudes.)