I've recently been interested in taking welding to a whole new level.
http://www.youtube.com/watch?&v=A10XEZvkgbY
https://www.youtube.com/watch?v=iLndYWw5_y8
https://www.youtube.com/watch?v=GRrXO9GSUPk
http://www.youtube.com/watch?v=Ao319dj6kiM
The free Ubuntu Linux CNC software is capable of running a home built 3D printer.
http://www.linuxcnc.org/
Online communities are developing and sharing their designs.
http://www.shapeways.com/
