I've done entries on personal fabrication and 3D printing (printing organs...). Until this point, these techniques have been applied mostly to software materials. Now it's been extended to printing 3D objects directly in metal. The current process is called Electron Beam Freeform Fabrication, or EBF3. This technique is essentially computer controled arc welding.

3D fabrication is definitely continuing to advance and even has its own open source project (RepRap) that started back in 2005 and continues to progress. Commercial 3D printers have broken the $5K barrier and are starting to be used more commonly, for interesting applications like allowing people to have their own WoW figures created in 3D.

One of the themes for sustainability is to move bits not atoms. 3D printing allows you to move the plans to the location and then create the part -- another example where IT techniques are effective in a new way to improve efficiency -- green IT.