Ok, this is a weird Orwellian concept that for some reason makes me want to try it out.  Here's the description:

The Epidigital Patch leaves the user with an animated topographic time-keeping image on the skin. The patch is impregnated with nanobots that are absorbed into the basal layer of the epidermis and interact to create the ever-changing surface graphics. Composed entirely of organic matter, the nanobots dissolve after several days at which point a new patch can be applied.

Now, apparently this company is a design firm for a lot of different companies.  Because of this, I'm not entirely sure that this is real.  In fact, I'm almost willing to bet that it isn't (i.e. 99.95% sure).  But you're able to do some pretty strange things with science, and nanotechnology is one area that I'm pretty sure is being researched heavily.  Anyway, here's the link:

http://www.oneandco.com/casestudy_08.html

Click on the #3 underneatch the picture.  Also, for some reason #2 just disturbs me.  “Well gee, my watch says I have only 1 more day to live...what shall I do?”  Thanks but no thanks.