I have a little notebook that I keep project, yarn used, gauge...all that important info in. I am going to be getting a page up where I can keep all that on my website though. I'm getting techy with it.
I do have a spiral binder that has the label to all my yarns in my stash, and all used yarns, with a little 2 inch piece of the yarn. That is the extent of nerdiness I am revealing right now.