Seems to have a lot of good reviews and testing:
http://www.thync.com/
"The intended use of the Thync System is to deliver pulsed neurostimulation waveforms to modulate psychophysiological arousal for lifestyle or wellness applications. The Thync System is not intended to treat or diagnose any disease or medical condition."
It is designed to be used for relaxation or stimulation, and costs $199. I might stick with listening to music at the moment though.






