Gerardo64 at the Google Earth BBS has created a file containing global overlays of several datasets available from the NOAA Environmental Visualization Laboratory. The data used to create the maps is collected by satellites and is updated every day.
The following layers are included.
Land Surface Temperature Sea Surface Temperature Snow [...]
The ac network weather blog has created a Google Earth layer to display current METAR weather conditions from NOAA for many regions throughout the Earth. Just find the location of interest and click on the dot. The pop-up balloon contains a link to a website with additional information about the station/airport.
This is a collection of historic maps and birds eye images of Washington DC during the late 1800s and early 1900s. The collection includes 58 highly-detailed topographic maps that appear to have been completed in the 1870s and 1880s of the outlying areas of Washington DC. These were a bit tricky to georeference, but [...]
This archive of Hurricane Katrina data has been removed. The aerial photographs of New Orleans shortly after the flooding can now be found using the historical imagery in Google Earth. The MODIS satellite imagery of Katrina can still be found using the MODIS Satellite Gallery. Much of the other data [...]