My favorite is the illuminati conspiracy that sprays aluminum out of jet contrails so that the sunlight will be reflected back, or something, and therefore, population control.
I may have skipped a few of the steps in that logical sequence. :)
Check this out
http://contrailscience.com/map/ It's an earth map of contrail activity, animated. Super cool and it's your new ant farm to watch.
play with the "contrail length" under the "animate" tab.
Just because they're crazy, doesn't mean they're wrong.
-Tom