In the Wikipedia “Poverty in the United States” entry, there is a map of the US shaded with the overall poverty rates of each county. It was made by user TastyCakes (thanks!) using this script, this blank .svg map of US counties, and data from the census bureau.
I modified the script a bit to include functionality for creating an HTML legend rather than a wikipedia one. Here’s the census data reformatted to work with the script. (Got rid of extraneous data and merged the state FIPS and county FIPS columns into one.)
Here’s the same map as on the wikipedia article, but in green. (TastyCakes script has a green color spectrum option.)
I converted the .svg to a .jpg using this online converter.
Cool, huh? Now all I need is some interesting data per county in a .csv file, and I can make nifty maps!