Science fiction becomes boring reality.

Muse is a light-weight, wireless headband with 4 built-in brainwave sensors based on EEG technology used in the medical community since the early 1920s.  These sensors detect the levels, combinations and proportions of the five key types of brainwaves to reflect your most intrinsic state of mind.

via Muse – The Brainwave Sensing Headband : Home.