View the moon and planets too on Google Earth
Alan Noble wrote The Art of “Goography” using Google to teach Geography for Victorian Geography teachers but its links to other “how to” instructions make it a good starting point to anyone getting into Google mashups
I am a great believer in giving examples when trying to explain technology and its benefits. Here are some great ones from the UK
http://www.iggi.gov.uk/caseStudies.php
Digital Switchover started on October 17th 2007 and involves converting every UK TV transmitter from analogue to digital. The BBC uses GIS data to predict the coverage areas of these transmitters across the UK and so to provide advice to consumers who might need to change their receiving aerials.