DIYer Josh Billions has created an ingenious solution for testing out different routes while biking. Called MapBag, Billions' creation combines a portable bag with a special GPS system that allows him to try different transit paths (without having to consult a map or listening to a typical GPS repeatedly tell him that he has taken the wrong course).
MapBag is worn over the shoulder, with a strap that sends vibrating alerts. According to TechNewsDaily, the wearer simply enters his destination and the vibrations tell the rider what direction the destination is relative to where he is. Essentially, MapBag allows you to find your way to your planned destination despite detours or if you want to a try a different way to your destination.
For your own custom MagBag, email Billions and be prepared to pay $400.