My primary desk for the last twenty years or so has been a door that I stained and added a fir border and collapsible legs. It gives me a huge workspace, and it reminds me of my grandfather, who helped me make it before I left for college. However, its surface is not perfectly even, so when I added a nice aluminum-frame mechanical keyboard a couple of weeks ago, the keyboard rocked.

Today it occurred to me to ask my wife for some help, and she suggested a piece of felt under one of the legs. I put the felt under the whole thing, and it worked perfectly. Plus it looks kind of cool against the coiled cable.

Yes, I know they make desk mats, but this solution was already sitting in our house.