Andrew Kelley, the creator of the Zig programming language, live-codes an assembler in Zig to understand how assemblers work. Starts around 5:00 in the video.
A wonderful primer on cybersecurity concepts ranging from phone phreaking to cryptography, complete with exercises! This is incredible if you're new to cybersecurity or looking for materials to help teach people who are.
A compiler for a simple language using LLVM.
A principled exploration of the author's philosophical approach to computing in general and debugging specifically.
Sequence and tune this software organ using math expressions
A programming language aiming for control and simplicity, similar to C but with fewer sharp edges.
A Git client for Plan 9. It's only 7,000 lines of code (1.1% the size of normal Git). As a bonus, check out the last line of the screenshot to see how the screenshot was created.
A DNS server written in Rust.
A program that lets you store a secret message in an image. The image below has a secret message in it!
You can use it to display animations, text, and arbitrary data. It also supports plugins, so you can build more powerful APIs on top of it.