Ours are not exactly small, and therefore we'll probably not be able to handle what's being called "the world's smallest cube puzzle". It's available at ShapeWays
It's a classic 3D puzzle with tetris-like 3D shapes. The only catch is that they are really tiny, with the maximum dimension being only 7.5mm! Fortunately, there are only 3 pieces. Spoiler alert: the solution is shown at the end of the video, so if you can't solve a 3 piece puzzle, well, um, we're kinda wondering about you.
This got us thinking. How small could you make a 3D puzzle? Considering the amazing 3D resolution of recent 3D printers, you could make them much smaller than this. So small you might easily lose them if you sneeze (or even inhale them!) The problem is not the printing equipment or the designs; it's our fingers. Fingers have a maximum resolution that won't change as there are no upgrades expected. At least for a while, anyway.
Via YouTube (Hat tip to John Barundia)