- What is the most interesting thing you have seen done with a 3D printer or 3D printing technology?
The most interesting thing I have seen done with 3D printing technology has to be titanium face implants for replacing deformed bones done by Layerwise. What something less 'special' but still something that really peeks my interest is all the art/statues created with 3D printing that can ONLY be created with 3D printing! Moving and interlocking parts, weird surfaces shapes, etc.. if you can think of it; you can print it.

- If you could build your dream 3D printer, what would it include and what would it do? Let your imagination run wild!
The printhead should move like a 5-axis CNC machine! That way you can build parts by moving the head in 'hollow motions' to really allow for the best buildup of the part.
Having a 5-axis head will also allow for an easy transition in giving the printer milling functions too.
AND having a 5-axis printhead in combination with a scanner will allow you to print material ON TOP of an existing part! Have any broken parts? No problem; place them on the printer, scan, adjust model, print. Have no idea what the practical functions of this could be... but somebody will have a purpose for it.

Also; there should be way more sensors in this 3D printer; it should read every part of the proces; every bit of heat in the part so that it can adjust the speed and temperature on the fly to allow to have a completely fully automated process. Basically, the printer should really be just click and print - no failed prints!

Furthermore; options like different colors in a inkjet-printer kind of way. One head that mixes the colors on the fly to create full color models.