What is the most interesting thing you have seen done with a 3d printer? The creation of a life sized elephant. Shows there are no limits to build size. Also printing of multi component interlocking items that could not be made any other way.

If you could build your dream 3d printer, what would it include and what would it do? 2-4 extrudes, heated bed, temps up to 300 C. Ability to stop and resume prints after changing material. Built in camera and octoprint. Open source. Readily available spare parts. Material dryer and a hopper for pellets instead of a spool.