Is there anything else you should be doing, in order to achieve what goal? Understanding all of the posts on HN? I finished my computer science degree ten years ago, and I don't understand all of the posts on HN! There's just way too much breadth to seriously keep up with it all.
Specific technologies may or may not be interesting for you. Is Git (or Github) terribly important? Maybe not. But you should aim to understand version control in general, and learn to use at least one version control system.
Open source projects? Thousands upon thousands, many of them defunct or floundering. Read about the history of GNU, and Linux, and maybe some of Eric Raymond's articles from the 1990's. That should give a decent foundation as to what's going on in general.
Computer science topics build upon each other. It's woefully out of date now, but look up The Hacker's Dictionary (aka Jargon File) and peruse whatever entries look interesting. The specifics are mostly obsolete, but the concepts, and more importantly, the character, spirit, attitude of hacking described there persists.
Get familiar with some classic stuff in the field. Write a few small C programs, if only to get the feel of what C is like. Try your hand at some Lisp (or maybe Scheme) programming, to see what that is like. Read biographical sketches of important people in the field (maybe start with Dennis Ritchie, John Backus, David Huffman, Guy Steele, John McCarthy, Donald Knuth, Richard Stallman) and learn what they have contributed. When was the first computer built? When was the first IBM computer built? What was Digital Equipment Corporation? How does a DEC PDP-11 compare in computing power to your mobile phone?
Go to the library and look up Knuth's Art of Computer Programming. Read the table of contents. Read some of the text. What's MIX? Implement the algorithm to calculate the date of Easter in the programming language of your choice. Try to solve a few of the exercises. Now that you've been exposed to Knuth, you'll know it's there if you ever need it.
But that's all background. Ours is an engineering discipline, in the sense that we strive to build products that help people do something. Poking around with technology for the sake of technology can be enjoyable for us, but perhaps not very fruitful for the rest of the world. Who are some people you could help? Does your barber have an online scheduling system? Do they want one?