This is going to sound awful, but sometimes I get sudden inspiration when I'm rating articles on Helium and run into one that seems, at least to me, to offer ideas that are so "nuts" I'm suddenly inspired to write my own article. (I may not write that article on Helium, but the inspiration remains, regardless of where I write it.)
Have you tried to going to some writing sites where everyone can write, look for subjects that kind of interest you; and see if you can find something that bugs you or makes you out-and-out angry enough to write? Or, with a more postive approach, have you gone through your own life, house, interests; and thought about things that have meant the most to you for one reason or another? Sometimes that kind of thing can get some ideas going. What about things going on in the world that drive you nuts, make you angry, or inspire you? Essentially, scan your brain, the room you're in, your home, your neighborhood, the rest of the world and writing sites for things that strike you one way or another. Keep scanning until you hit something.