I'm not a member but I think what she does is choose a fiber/colorway for the month and everyone gets the same thing. I've seen some of the months' colorways on Ravelry and they have been very cool I think it's really neat to see the same roving spun up by different people.
I'm too picky about colors to join a club where they surprise me, though
You can see a few of the colorways here:
If you google further you might be able to find some more