When I stepped out of my office last evening on the way home, the sky was really dramatic - overcast, but with a lot of texture in the clouds. The fading evening light shone through a translucent gauze in places, while other parts of the sky were obscured behind thick clouds. I exclaimed to Kali, "Isn't the sky wonderful right now? I've got to take some pictures!" to which she replied, "It just looks cold." (It wasn't cold; we had a record high of near 70 degrees F yesterday.)
I ran to the house and managed to get some shots. I think the effect was better a minute earlier, but I didn't have my camera with me then, so these will have to do.
I took the last image, below, up into the canopy of the huge, 250-year-old sycamore tree growing directly behind our house. I think that the camera rendered the sky almost indigo, but it simply was very dim just before all the light went out of the day.