While not gadget related, this a pretty cool web site. Nikon’s Universcale lets you compare the size of objects from the microworld to the universe, from a single perspective. On a single scale you go from protons measured in fentometers to galaxies measures in light years. By setting them up against a scale, we are able to compare and understand things which cannot be physically compared.
The scale is set up such that each time you move an order of magnitude up, the previous order of magnitude will fit into a small square on the left of the scale.
After seeing this, it’s hard not to feel small!