My friend John K and I tried another daily journal concept this past Spring -- find an old hardback book somewhere and draw on the pages using words or concepts as a prompt for an idea of what to draw. He found us a couple of used Agatha Christie mysteries that were a good size and had nice paper, and off we went!
I'm done with mine now. I have to admit it was hard to do -- mostly in my book (Curtain) people sat around talking, so not much in the way of cool ideas. I did work on character, though. These are two examples: Poirot's temporary valet and some other guy who liked to watch birds and turned out to be the murderer.