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

On robo 3d site I saw a full sized scooter that was 3d printed and was really cool. The full color sandstone prints that thingiverse makes are really cool looking. I also think that really any 3d print thay is useful is great.

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

My dream 3d printer would make prints directly from pellets, so the cost of expensive prints would no longer be a problem. The 3d printer would print items with no geometric limits, with support material. It would also be full color, not like the FDM full color printers not that can change color by layer, but be multicolor within the same layer.