A team of researchers at Heriot Watt University's School of Engineering and Physical Sciences, in conjunction with Roslin Cellab, have developed a 3d printer delicate enough to print stem cells. They plan to use it to make miniature 3D human tissue to test pharmaceutical drugs, cutting out the need for animal testing.
The use that fascinated me was to print a tool in the space station from a design emailed up from earth. I am just waiting now for a replicator to print out tasty nourishing meals without shopping preparing or cooking. I suppose we will still have to wait weeks for a repair man to come when it breaks down.