PocketMod is a website and freeware program that helps make 8-paged mini-booklets and organizers out of a single sheet of paper. You can make them online by selecting from a series of templates of what goes onto each page, including calendars, graph paper, to-do lists, etc. Then print out your design on a sheet of regular 8.5″x11″ paper, follow folding instructions and voila!
I carry a bunch on me, all within easy reach so I can just whip ’em out and record whatever idea before I forget. I even set up ones for particular projects so I can share them with clients. I hold them together with a rubber band in my back pocket, and then when I’m done with the project I just bind them all together.