My entry:

- What is the most interesting thing you have seen done with a 3D printer or 3D printing technology?

Our InBloom dress a 100% 3dprinted dress is perhaps the most interesting and challenging 3dprint we've done on an ultimaker www.xyzworkshop.com/InBloom

- If you could build your dream 3D printer, what would it include and what would it do? Let your imagination run wild!

A nano-particle 3d printer that reconstructs atoms to print any material in the world including admantium! And cause it prints atoms it could also print you another 3dprinter! And of course print things in measured in nanoseconds. ~patent pending~