Time.com just posted a great list of top ten Google Earth finds. If it's got you hungry for more, the best place to find out about the weirdest, coolest things to see is always the Google Earth Community. I've been checking out the "Huge and Unique" forum, where users have posted hundreds of placemarks that you can download and view in Google Earth.
And it's easy too. If you're new to the community, look for attachments in the threads that interest you. Clicking on them will open a placemark, set of placemarks, or overlay right in Google Earth, and you'll see it in the Places panel. With finds like World's Biggest Sculpture and Faces in Google Earth, thanks to other users I'm well on my way to creating my own personal top ten.