There was an interesting article on Slashdot yesterday about Hacking Our Five Senses and Building New Ones that contained some interesting links about new types of input to our brains.
One interesting thing that was brought up was having an innate sense of direction, and how this could be accomplished using technology. A research team made a belt that had several vibrating motors on it, that would always vibrate toward North. After worn for a while, apparently the brain began to process the information implicitly and the information becomes incorporated into your awareness. Sounds pretty cool to me! Here's a link to information on the compass belt.
I started looking for more information, and found a smaller design for an anklet. It looks a little less conspicuous - I'd consider building one of these just to try it out. :)