Freemind mind mapping tool
Freemind is a good mind mapping tool I use as an aid to long-term memory. It allows you to put ideas down on something more permanent than paper and then group and order them into something meaningful. Something akin to long term brainstorming. This also promotes focus as the idea can be left safe in the knowledge you can pick it up later. Free your mind!
I use this tool to save ideas for blog posts and was the inspiration for this post. I have also used it to record events that occur during team member absence. There is a handy export to html or jpeg functionality for sharing.
You do need to have Java Runtime Environment 1.4 or later installed on your system.