As I was researching for my story about how humans could be the ones who are aliens to the planet, I came accross the ever so intriguing phenomenon of crop circles. And not too late in the research I came accross this website created by the, oh so mysterious crop circle makers. Yes, that's right. They are works of art. (I recently saw a documentary on the National Geographic channel that did not cover this aspect of crop circles)
http://www.circlemakers.org/case_history.html
They even have a beginner's guide to making crop circles. Although, at some level, I am disappointed that no one from other planets is interested in meeting us.
Enjoy!