Who Makes Crop Circles?

Tanhill Crop Circle

I watched a program on crop circles last night on TV and was totally unconvinced that there is anything spooky or extraterrestrial about them. I would like to congratulate whoever is doing them on their excellent and beautiful designs. I wonder how one can join one of the clubs doing this? It is a bit funny, I think, that people imagine these things might be messages from beyond. I looked at a website showing some of the recent designs and they are so clearly human symbols- of course this is just an intuitive feeling on my part, but I would certainly be willing to bet on it, if anyone cares to make a wager.