I had been contemplating diving into Ruby for a long time. I'm currently actually auditing a course on Ruby. But once I fired up Node most of that motivation to learn a new back-end language went out the window. The thing is, I really enjoy doing stuff in the terminal and writing scripts that will do things for me. Automation, as we say. This has prompted me to learn a significant amount of bash scripting (used for Z shell of course), but that has it's own limitations, and it was never really designed to be good at many of the things I would want to do from the terminal.
PHP works as a scripting language, and it's already my go-to language for development, but the lack of well known PHP shell scripts made me wary. Whereas Ruby and Python both have a ton of excellent scripts under their belt, PHP just never seems to have caught on outside of server-side scripting. This may be changing, as Composer makes it abundantly clear that one can do awesome things with PHP on the command line, but I still wanted something different.
What Node has done, is freed JS from the confines of the browser. By adding allowing it to be used on a server or in a terminal it now has what it needs to truly become ubiquitous. This is all in addition to an emerging trend:
Today we have things like CoffeeScript and TypeScript as well as an array of tools for compiling probably anything you would care to develop with to JS. These include compilers for C#, Java, Python, C/C++, etc.