I want to share a project I've been working on: a handcrafted virtual stack machine with a reduced instruction set. The programs for the VM are written in a minimal, dynamically-typed, Turing-complete programming language featuring basic data types, pointers, functions, structures, and flow control. The project's goal was purely educational, and I'm more than satisfied with the outcome, having learned a ton of stuff. I recommend going through this experience to anyone interested in how programming languages work.
Shout-out to Bob Nystrom whose book[1] has been of immense value from the beginning of the journey.