Very cool shit. NASA is using 3D metal printers to make parts for the Ares rocket J2-X engine. The engine is based off of the Saturn V. Turns out, if you have a strong enough laser, you can do a whole lot more than make silly plastic parts- you can zap damn near any metal into ready-to-use shiny metal parts. It's called Direct Metal Laser Sintering.
http://blogs.nasa.gov/cm/blog/J2X/po...869180794.html
http://www.youtube.com/watch?NR=1&v=1CizD2YLTGg