Here's a very interesting 3D printer design that uses the lit pixels of a smartphone to harden resin as the gantry lifts. Super-simple, cheap ($100) and designed in Taiwan, this may end up being the easiest to use printer yet. Just load up the model, let the screen change which pixels are lit at each layer, and wait for your mini to be created (upside down) before your eyes.
If you go to the link above you can see it in action.