Those clever boffins at the University of Bath, England have managed to develop a machine called RepRap which can, effectively, replicate itself. The boffins themselves describe it as being a 3D printer which can print, or rather produce, real mechanical parts. Perhaps most interesting is the claim that RepRap can actually copy and produce the parts needed to build another RepRap. In other words it is a machine that can replicate itself.
RepRap itself stands for Replicating Rapid-prototyper and works by building up the component in layers of plastic to produce something akin to a Lego brick in terms of robustness. Sure, there are other 3D printers out there but most are hellish expensive. RepRap did not cost tens of thousands of pounds but less than a thousand.
Best of all, it's open source. The developers say that "following the principles of the Free Software Movement we are distributing the RepRap machine at no cost to everyone under the GNU General Public Licence. So, if you have a RepRap machine, you can make another and give it to a friend..."