= aiming to create an open-design construction set
"aimed at providing structural metal frames for DIY 3D-printers, milling machines, or robotics" 
"Contraptor is a work in progress aiming to create an open-design construction set, with CNC and Cartesian robots in mind. It consists of perforated aluminum angle of various lengths (Erector-style) and linear sliding elements actuated by belts and threaded rods. One of the goals is manufacturability at home with basic tools, using inexpensive materials and parts readily available in hardware stores and online." (http://open-innovation-projects.org/projects/show/86/contraptor)
"Contraptor is a DIY open source construction set for experimental personal fabrication, desktop manufacturing, prototyping and bootstrapping. Various Cartesian robots can be quickly assembled from Contraptor and used as a platform for projects such as XY plotter, mini CNC machine, 3D printer etc.
Contraptor is an ongoing project under development. One of the original project goals is manufacturability at home with only basic tools, using inexpensive materials and parts readily available in hardware stores and online, with cost in the range of $400 and without the need for a custom-manufactured kit. In addition to DIY plans, we're also working on Shopbot-able kits that can be manufactured in small quantities by anyone willing, from open source drawings.
You can create things with Contraptor without having the actual set. 3D models of Contraptor components are hosted on Google 3D warehouse and can be downloaded directly into Sketchup - a free 3D modeler that is gaining popularity because it is very intuitive and easy to use. If you prefer other 3D apps, DXF exports of "official" components are hosted on Thingiverse, a cool new site for sharing hardware designs." (http://www.contraptor.org/about)
Promises to accelerate many ad-hoc/grassroots developments in personal fabrication. Great platform for educational purposes Demonstrated several working machines, some targeted to hobby market (like entry level CNC machine)." (February 2010)
Status update via http://open-innovation-projects.org/projects/show/86/contraptor