An extensive, clear explanation of how to write a lambda calculus interpreter in Haskell.
Book Wyrm is a federated alternative to Goodreads that lets you track what you're reading and share it with friends. Try it out here: http://fedireads-test.glitch.me/
A narrative scripting engine similar to Ink (http://github.com/inkle/ink), but more portable and implemented using Haxe.
Brian gives a deep explanation of how Monte Carlo Tree Search (a key technique for game AIs) works. He implemented the AlphaGo paper from scratch, so he should know!
A small, readable, self-hosted Lisp to C compiler.
A nice overview of Vim 8's native plugin support and how to migrate to it from Pathogen.
A CHIP-8 (https://en.wikipedia.org/wiki/Chip-8) interpreter written in Rust.
An introduction to shaders, including how to make a 3D animated spinner.
A tool for turning text into braille dotgrids.