As I explain on the GA course, files which are created using Google Earth are generally saved in KML format. This is short for Keyhole Markup Language.
If you are particularly keen to find out more, I have a book about KML which provides plenty of information about the language.
What files are available out there ?
Well, to show what can be found, I did a quick Google search on the term 'kml geography' and came up with some interesting files within a couple of minutes:
- a file released by the US Data.gov website showing radiation levels in and around Fukushima.
(follow the link, and use the search button, and there are over 700 files apparently for download on a range of topics) - US based, but plenty on tornadoes, hydrology, hurricanes etc.
- information about files which have been made available by the Office for National Statistics (as well as shapefiles which can open in ArcGIS Online if they have less than 1000 elements to them)
- teach a bit of RE too ? check out these BIBLE files
- wildfires in your spec (Edexcel 'B' for example) - go HERE and click DATA to download KML files for current fires (depending on the season...)
Don't forget the old KML Factbook as well