3D printing is a really interesting technology that’s quickly gaining steam. With a 3D printer (like the RepRap), you can quickly make everything from shoes to your own parts for long-dead technology to your own action figure souvenirs. Future (and much larger) 3D printers might just build your next house for you.
Today’s 3D printers are the direct precursor to science fiction devices like Star Trek’s replicators and the replicator-like nanotechnology device in Neal Stephenson’s The Diamond Age. It’s fascinating to think of a day when your kids can be kept occupied by an endless number and variety of toys cheaply created by your own living room 3D printer, or the structure of a house can be created in twenty-four hours with a large but fairly simple machine and almost no manpower.
The “no manpower” part also concerns me a little, but that’s for another post.
EDIT, 2011-06-02: 3D printers can now print working keys too.