I've started dabbling in the Linux operating system, for two reasons -- the Raspberry Pi (a $30 single board computer that runs on Linux) and losing the PIN code for my Bitcoin hardware wallet (which I recovered using an old MacBook Air running Linux). If you are interested in Linux but don't know where to start, Lifewire has a good tutorial on how to install Linux Mint (one of the many different free distributions) on your Mac or Windows machine without overwriting the existing OS.