Science nerds, rejoice!
River Runner enables you to “drop a raindrop anywhere in the contiguous United States and watch where it ends up;” 3D Periodic Table offers up all sorts of customizations, like sorting elements by their atomic radius or electronegativity or abundance in Earth’s crust.
Keep in mind that these are under the headline “Timewasters” for what should be fairly obvious reasons. I therefore cannot be held responsible for any loss of productivity.