If you enjoy biking this Open Source Smartbike project will be of interest to you. Luis Cruz who brought us Eyeboards last year is now enrolled in the University of New Orleans and has started this new project. Luis will make the code and schematics available in December so you could make your own. If you would prefer to buy one you could support his Indiegogo.
“The Smartbike is a virtual reality game that you can play on your PC with your own bicycle. It consists of the hardware that has to be adapted on someone’s bike so the software can read the speed of the bike, the direction that the bike is going to depending on the handlebar’s position, the heart rate and the calories burned throughout the game.”