When you've been bitten by The Strobist bug, you sometimes get wrapped up in all the equipment and such. So much so that it's easy to forget that at it's core, The Strobist philosophy is really nothing more then thinking about and controlling the direction and quality of light.
So after you've shot a large number of frames using off-camera flash and modifiers like umbrellas and softboxes, you can start to think about and appreciate how to get the same effect when you don't have that gear available.
And there is no better soft box than the big, giant one in the sky that you get with a thinly overcast sky. No flash needed. Just get the directional light positioned for a bit of rim or back light, expose for nice, saturated colors, and fire away.
