This is the notebook where I keep my to-do list, like the one you can see in the picture in Book Review: Do It Tomorrow. A quick and cheap way to have a small multipage notebook you can always keep with you. Of course, calling this origami is a small lie, as you have to use scissors.
I read a very good post about going the analog way (How analog rituals can amp your productivity) and this was my tool. I could have gone the Moleskine way (I have a pair of 7 odd cm sized pocket notebooks), but this is way cheaper and more handy. When you need one, you only need a A4, it can even have a side written up!
Also, when you finish your notebook, you can unfold it and fold it reversed to have another use!
You will need an A4 (or any other size) paper and scissors.