As the title suggests, I have spend a couple of hours today testing Galvanic Vestibular Stimulation (GVS). The theory is that a voltage applied to the mastoids (the small bone right behind each earlobe) will screw with your balance system, effectively creating a "pull" towards the anode.
Well, I made a couple of home-made electrodes by layering the stripped end of a wire between duct tape and aluminum foil (the kind found in any respectable kitchen), attached them to a DPDT-switch so I could reverse the polarity of the electrodes, and stuck them to the skin behind my ear. Balanced on one foot, flipped the switch...
...and very nearly fell flat on my behind! :o
The whole thing is so simple it's hard to believe we don't ever see people experimenting with it. A 9V battery, a couple of electrodes, and 1-1,5mA of current.
Try it out if you haven't already! It quite literally nearly floored me to experience this, the effect is quite pronounced!
As to practical applications.. The first thing that comes to mind is navigation systems. You could integrate this with your cellphones GPS and compass and have electrodes cleverly hidden in a pair of headphones gently "pull" you in the direction you need to go. You could experience something very similar to centripetal force when playing driving-simunator type games. There are probably other applications as well like, say, having fun with electronics. :D