The following are all taken from photos of REAL crop circles.

For all of my drawings, the yellow areas are the parts that are mashed down!

Here are some pretty simple crop circles.  Do you see how these could be made if you had two people, some rope and a board to mash the wheat down?

crop circle graphic
One person would stand in the middle (holding the rope) while the other
walked and mashed.  You'd just
change the length of the rope to make
the different circles.
crop circle graphic
You'd need to map out the triangle first...  Say you had three people...
How would you do it?
Would you need four people?
Remember that you can't leave any evidence (like holes in the ground)!
crop circle graphic
This one must have been designed by
girl extraterrestrials! 
crop circle graphic
How many circles do you see on
 this one? 
This crop circle was 300 feet wide!
crop circle graphiccrop circle graphic
crop circle graphic

Here are some crop circles that were made out of hexagons and triangles.  They were pretty easy to make on my art program, but I don't know how the heck you'd make them out in a field in the pitch dark of night!  Can you figure it out?

crop circle graphiccrop circle graphic