USA CO2 Emissions
Simon Ilyushchenko, a Site Reliability Engineer at Google, has used his 20% time to produce this Google Earth Browser mashup of CO2 emissions in the US.
The map shows data from Project Vulcan, put together by a team of scientists at Purdue University. The data shows detailed emissions for all 50 US states in 2002. Using the map it is possible to see which US states and counties have the highest and the lowest emission rates - absolute or per capita. You can see where people burn more gasoline for driving, or where they use more fuel for heating and cooling their homes and businesses.
There is even a video fly-through of the map:
Via: Google LatLong: Mapping CO2 emissions