Just watched this TED talk today[1] and mentioned to a friend that 3D printing is going to be "really, really cool". While the video probably won't show anything new for your average hacker here it might be a good introduction for people around you.

Creating a lower jaw within a few hours is "really, really cool".

[1] http://www.ted.com/talks/lisa_harouni_a_primer_on_3d_printin...