This may exist, but the title of the site would seem to preclude finding it. David Allen describes a method for organizing physical documents using a set of 43 folders. I'd like to have something equivalent (or even better) for OS X. Specifically, if I have a document I need on a certain day (say the agenda for a meeting), I'd like to put it away so that it will be associated with that date. I could probably roll something use WordPress or similar software, but it would be even slicker to do it with iCal or some local application.

Does such a thing exist?