A very cool new program: Mindscope. There are a couple of ways to describe it: a pinboard, a way to enter text, drag it around a screen, nest other text under it (so that clicking an underlined entry opens up a new board with new text), draw arrows connecting things.
It runs on iOS. Here's a picture from my iPad:
As you can see, I just set up a very simple grid that allows me to track some of this week's projects. It's really easy and simple to set up, drag things around, file when you're done. For those of us who sometimes need a couple of systems to stay on top of our world, this one is a keeper.