The blog io9 has such cool stuff. This article has a series of unusual landscape photos that (to me!) look like they could be from Minecraft.
These crazy circular patterns are because of something called “center pivot irrigation”. From Wiki —
Center-pivot irrigation (sometimes called central pivot irrigation), also called waterwheel and circle irrigation, is a method of crop irrigation in which equipment rotates around a pivot and crops are watered with sprinklers. A circular area centered on the pivot is irrigated, often creating a circular pattern in crops when viewed from above.
If you would like to make your own variation, here is a template for making circles in Minecraft…
If you click on the link, you will get a much larger version of this.