An old Dell workstation that I stole from a corporate job I used to work. I stole a few of them, actually, and used the parts from the others to upgrade one of them. For a computer that would probably not be able to run Minecraft, I now have a headless home server that uses the Servarr suite to fetch and stream media from Usenet to all the devices on my network. It works so well, I have it running an Audiobookshelf server as well, loaded up with books I get from MAM.