There is no doubt in my mind that there are human circle makers creating these things either for their own pleasure, or as a hoax (for whatever reasons they may have). But I also have no doubt that some of these things are caused by some unknown phenomena. There are many theories floating out there about what could cause some of these things that humans are not creating on their own.
May I suggest a great movie to check out regarding the Crop Circle issue?
Crop Circle MovieI really enjoyed this documentary and most of my skeptical friends are really having "second thoughts" about the fact that these are all created strictly by human circle makers...
Now, there is no doubt that these were created by a human:

or this:
But you can not tell me these were created by humans, undetected, in a matter of 4 to 5 hours, in one night no less, with only wooden planks and a flashlight... as these circle makers claim they can create these things!!!!
