RepRap is short for Replicating Rapid-prototyper - a project to create an open-source self-copying 3D printer.
RepRap version 1.0 "Darwin" can reproduce 60% of its parts. The machine is manufactured from plastic and metallic rods. Next version RepRap 2.0 will be called "Mendel" it is author's incentive to commemorate famous biologists in the names of replicative machine designs. After all, they say it is mimicking biological evolution in the ability to reproduce himself. On my part, I would be very carefull to make long standing comparisons between RepRap and working evolution in action, since in biological evolution we have evolution of designs and here it is materialistic reproduction of human invented improvements, without any hints of competition and struggle for resources between different blueprints.
Nonetheless the project is alive and kicking by enthusiastic opensourcenicks. It is also loosely connected with another hardware open source project Arduino.
3D printing is nothing new, in fact, aside from RepRap there is ongoing push for introducing such devices right on your desktop.
For approx. 5000$ you can purchase Desktop Factory 125ci 3D Printer from "Desktop Factory"
In size comparable to early laser printers, uses an inexpensive halogen light source and drum printing technology to build robust parts layer by layer from composite plastic powder.
The cost of the build material is expected to be about $1 per cubic inch.
Those two examples are using different technologies, different input materials and more importantly different philosophies about how and who is going to use 3D printers. Certainly open source 3D production would've make a tremendous blow upon existing capitalistic system, but to make usefull things you need to be educated and to have IQ well above average. The real evolutionary struggle is between two worldviews : one seeing a lot of consumers and a handfull of creators, alternative claims - everybody can be a creator.