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.