One of the pillars of a good GTD implementation is the ability to capture ideas or thoughts in writing whenever and wherever they occur. This can be a problem when running, biking, or in other situations where one doesn’t want to carry something as substantial as a notepad or PDA.
Several months ago, I found a great solution to this problem: Take a pen (of good thickness) and wrap a sticky note around it, sticking it to itself. This works best when the pen has a clip, under which you should slide the sticky note. Please see the example below:
The clip is also good for holding the pen in your pocket, on your belt, or whatever. If you use both sides of the sticky note, the amount of writing space is actually pretty substantial.