I've mentioned in previous posts that I have a 10 year old laptop that I have kept running using Linux and other open source options. You can get versions of Linux that look a lot like Windows, but Linux allows you to do much more than Windows or a Mac could ever come close to allowing. Moreover, Linux is everywhere. Most supercomputers use it, most servers, all Android phones, and countless other devices. So knowing at least a little bit about it would be useful.
For those interested in learning, edX is offering a free course that is an introduction to Linux. The only prerequisite is that you have at least some computer experience.
So sign up and learn something new. I know I can't wait for it to start.