You've probably seen artificial skin before, but never has it been quite so... accurate. Japanese researchers have grown skin tissue that not only includes hair follicles, but all the glands that come with it -- including oil and sweat glands. The trick was to take cells from mouse gums, turn them into stem cell-like forms that generate skin, and implant those into mice with immune system deficiencies (which lets the new skin grow unimpeded). The resulting skin was a little creepy -- just look at the wart-like growth above -- but it was healthy, behaved normally and made connections with natural tissue.
The technique is still a long, long way from practical uses. The scientists estimate that human trials will only start sometime within the next 10 years. If it pans out, though, the discovery could be a tremendous boon to the medical world. If you're ever the victim of a serious burn or disease that destroys skin, you could get replacement tissue that's virtually indistinguishable from the naturally grown variety.