I've noticed that creative ideas often pop in at random times when I'm doing something unrelated to the idea. So I created a little script that, upon hitting the F10 key, opens a dialog. I type in my thought and it writes it to a file called jot.txt. At the end of the day, I review jot.txt and act on the ideas. This allows me to capture interesting ideas when they happen without losing my current train of thought.
If you're interested in adapting this script for your own use, I've published the script here: http://techiferous.com/2009/12/streamlining-your-workflow-wi...
As a side effect of opening the file up, rather than entering it in a dialog, it refreshes my memory each time I add a new idea.
Early on, I imagine that guilt about doing nothing during the creative blocks would motivate me. Over time, I suspect whether anything got done would roughly break down based on whether there is an explicit deadline. With no explicit deadline it would depend on how excited I was about a specific creative project.
If you're doing creative work for a living, I don't think that you can assume deadlines away.
