Painting weather?

Is it just me, or do other artists suffer from the winter doldrums? I have several pictures I want to work on, but on a dreary, gray day I just can’t seem to get the inclination to start. Then when I do start one, I sort of “fizzle out” before I finalize it. Sometimes I read magazine articles talking about how artists paint all winter so that they can do outdoor shows all spring and summer (now, that’s another subject altogether!). How do they do it?

Then, sometimes I go into a sort of “slump”, weather notwithstanding. Again, just can’t get it together to paint, do the whole whine-y “there’s nothing to paint, woe is me” thing.

What do you do when you go into a “slump” like that? What pulls you out, gets you going again?