A while back I posted a picture of my rain-cup downspout. At the base of it there is a rock with a hole in it, about half the size of this one just a few doors down. I think the previous owners were working toward creating something like this lovely treatment. I have to ponder what I can do that is similarly charming, without being a complete copy-cat.
You can find a variety of styles of rain cups and rain chains here. They are not cheap.
(Apologies for the poor photo quality; I was working from a different computer that only let me save it as a gif.)