Thought this was fascinating.

Apparently, the number of crop circles seem to have increased lately. Recent circles in the UK were made on Jul 07 and Aug 13 this year. Often, soon after the creation, mysterious black military helicopters come to the place of the wheat formation and they try to scare everyone away. They also use some sort of gas and one of the investigators measured a high level of radioactivity after the helicopters had left on 07-07-07.
A scientist investigating the crop circles, seems to think that the date Aug 18, 2007 (Saturday: tomorrow) would have a special meaning.


Link to crop circle on 07-07-07:
http://www.earthfiles.com/news.php?ID=1288&category=Environment

Military helicopters:
http://www.earthfiles.com/news.php?ID=1289&category=Environment

Aug 18, 2007:
http://www.earthfiles.com/news.php?ID=1302&category=Environment
This is all speculation, of course.

Fact remains that there is no plausible explanation for all crop circles.

There are many more interesting links, but if an article is older then 120 days, you'll have to be a paid member (30 usd).

Michel

edit:

PS.
Google video:
http://video.google.nl/videoplay?docid=-671103935589426...op+circle+helicopter
:-) Unfortunately, you cannot see the "white balls of light", allegedly due to Google's video compression.