Emacs as ultimate retrocomputing hobby

Emacs satisfies all of the preconditions for a retrocomputing hobby:

1. Long (fourty years), interesting, storied history and set of precursors
2. Maintains many aspects of its heritage, connecting you directly to that heritage (for instance, Emacs Lisp is a clone of MACLISP, the original Lisp Machine language, that exists nowhere else today)
3. A vibrant and passionate community regularly making things for/with it just for the fun of it, often some of it actually art (and a long history of that being done, given point one).
4. It can be completely understood inside and out, up and down, left and right, and modified.
5. It has a lot of unique properties compared to modern computing systems, deeply influenced by its history.

It also has many neat advantages over other forms of the hobby. Namely:

1. It can be very productively, justifiably, and usefully put to work in your everyday life
2. A lot of the things that you do with it as a hobby can end up benefitting your everyday life and work productivity
3. It's completely free!

This makes it the ultimate retrocomputing hobby!