In 1991 Doug Bower and Dave Chorley admitted that they had been responsible for the crop circles appearing in part of England and believed that they inspired others around the world. Doug Bower also had to tell his wife.. .from wikipedia
Bower's wife had become suspicious of him, noticing high levels of mileage in their car. Eventually, fearing that his wife suspected him of adultery, Bower confessed to her, and subsequently, he and Chorley informed a British national newspaper. Chorley died in 1996, and Doug Bower has made crop circles as recently as 2004. Bower has said that, had it not been for his wife's suspicions, he would have taken the secret to his deathbed, never revealing that it was a hoax.
They made it quite obvious that it was human work too, even going as far as to write their initials next to some of them. Another act was to make one in anti-clockwise direction instead of clockwise to show up a someone who had been discussing how they were always clockwise in the media.
Other groups like circlemakers.org have also shown that they can create just about any kind of pattern.
A large industry started up around crop circles and it is because of this industry that a lot of the ideas about it being aliens etc are still taken seriously by a few people who obviously missed the point because Bower and Chorley also said that they did it to demonstrate that a lot of pseudoscientists and UFO spotters were gullible.
All of that said, some of them do actually look quite nice and it could be considered an art form. Can't we just enjoy them on that level now?
Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too? - Douglas Adams