IMHO it's quite interesting that the different fans (experts or researchers...whatever term) of this phenomenon often try to differentiate between 'fake' and 'real' crop circles. [Here, I'm referring to physically down-forced grain spears, not manipulated picture stuff. Of course, I do not doubt that there's very likely 'fake' and 'real'
pictures.]
I think there's simply no difference between 'fake' and 'real' crop circles since I'm convinced they're created by some sort of human artist. So it's just circles. But obviously, the circle fans are just blindfolded by high quality artwork. And seemingly, as Padma stated, the avarage quality has increased faster over the years than they could adjust their fake/real classification. Now the 'real' ones do cause some headaches for them, so they start some measuring campaigns. Amongst other things, they detected a "higher" level of radioactivity on the circle area. However, the relation level of "higher" isn't mentioned. I *could* imagine that slighly some more Radon (radioactive gas) would emerge from the ground, possibly caused by an actually higher rate of evapotranspiration over the circle area. That would be a pretty much normal process. [I better stop now before I unintentionally become a total crop circle junkie myself...

]
Anyways, I am quite fascinated by this
artwork. The artists like to stay anonymous for what reason ever, just as...

...maybe there's not enough walls in the countryside to put a graffiti on.
From this
source, you can pick up some funky links, possibly even stuff in your native language (just click on "Links" on the left side of the page). There's a lot of pictures and (more or less weird) info found.
Some parts of the world, such as South America, seem to be circle-free. Maybe a jungle-pranking technique is just about to be invented...
All my pribble-prabble here aside, I hope there's still some space left for alien imaginations (if you have such).

