Last sunday I built a quick plug rack out of some leftover 1X2 pine I had laying around and a handful of dowels. I took two 8 foot 1X2s and clamped them together and then drilled 1/2 inch holes thru both of them about every 4 inches apart.
Then I basically just formed the 1X2's into a rough rectangle and put a couple of nails thru the top into an exposed floor joist in my basement.
I just insert the dowels where I want them thru the 1/2 in holes so you can have different width shelves depending on what you've got to hang.
I got a lot of EMPTY shelves.... But I'm working on that....
