The September issue of Wired has a nationwide map of marijuana prices (excluding Alaska and Hawaii, where people apparently don't smoke weed.) It's fascinating to see the price differences nationwide, but there are interesting economic points as well.

The map was put together by FloatingSheep, a group that maps and analyzes location-specific data. In this case, it took data from the Price of Weed website, which crowd-sources marijuana prices. As Floating Sheep explains, using that data it was pretty easy to create a weed price map:

After cleaning the data to get rid of the outliers, we created a continuous surface using a statistical interpolation technique known as kriging to identify the average variance among price differences through a spherical semivariogram model. To obtain a price for each location show in the map above, an interpolated value was estimated as a weighted average of prices from its twelve neighboring points.