My original method was to just move my project to I:\home\projects\dead.
After accumulating a few hundred of these, I started going back and reviewing what I'd accumulated - a short one-line description, and a screenshots folder, following a naming convention under a ".projnfo" folder (description.txt, visibility.txt, screenshots\*.png, etc.), with a quick program to accumulate these into a single HTML page overview. My latest iteration of this actually adds shortcut links to launch VS, git shells, etc. and dynamically updates, but ditched the screenshots (for now): http://i.imgur.com/gbj1Cr5.png . I keep telling myself I'll eventually spin off a public version of that page, but so far I haven't. But a common goal: Make it absolutely trivial/low friction to give something a quick summary.
Most recently, I'm now also trying to embrace the idea of "always be shipped (tm)" as a means of combating my tendency to get hung up on perfectionism - in the most extreme form, this means a public github project and an empty initial commit is my first push, the second commit maybe adds something that's actually usable, and the third commit is a .nuspec so I can package it and reuse it at a whim (completely ignoring the question of if it's even worth reusing.) This also encourages me to pick up an old project against instead of rewriting a whole "new and improved" version - easier to just fix the old one than go through all the effort of .nuspec s and new github projects etc etc etc... and in this state, "closing" a project is a simple matter of no longer committing to it. No cleanup necessary before making it public - it already was public!
I still have some projects that I never make public, or only make a github page public for though.
