Researchers in Germany and Hungary recently discovered that human skin produces a substance similar to that found in THC.  "Endocannabinoids," just like cannabinoids found in pot leaves, protect the skin from the drying effects of the elements (i.e. wind).

So can you get high off your own skin?  According to researchers, it is possible in theory, however it is unlikely for your body to produce enough endocannabinoids to make it happen.  But there is no harm in fooling your stoner friends into thinking the idea will work out--as long as they don't try to light themselves up.