The RepRapMicron Project, or μRepRap, is an extension of the Open Source RepRap 3D printer project that aims to bring micron-scale fabrication into very widespread adoption. The main project page is here. It uses hardware and software familiar to 3D printer developers, and materials that are easily and inexpensively available.

The meaty part is in the "maus" directory, where the OpenSCAD models for a rapidly reconfigurable 3D printed prototype can be found.

At present, the project is in the very early prototyping stages, figuring out the unknown unknowns. This repository holds files that can reasonably be expected to be useful to potential developers/experimenters, but at this stage there are absolutely no guarantees.

The proof-of-concept prints have already manufactured things between 8 and 30 microns in size.

RepRap is an open-source (hardware, software, and documentation) desktop fabrication system which lets you construct arbitrary objects (or parts for assembling more complex systems). It's unique in that you can construct one yourself for about $400us, and it is fully capable of making duplicates of itself.

An open source DIY robotics/rapid prototyping kit much like an Erector set. Lots of standardized pre-milled bars, rods, connectors, and components. Build your own plotter, CNC machine, RepRap, scanner table, or what have you. Capable of three axes of linear motion. Comes with all the electronics you need, including an Arduino, stepper motors, and a motor driver board.

An open source object scanner that exports the data such that it can be replicated on a 3d printer.