I've seen a lot of technical recommendations, but what I found most fun to experiment with is visual/art/music stuff, so here are some recommendation if that's also your thing. It's not strictly programming, because most of it requires learning more skills than just that, but I see that as an advantage. YMMV, though.

The Book of Shaders is and extremely good introduction to some basic shader stuff. Especially thanks to the interactive editor they have in their tutorials, and web tools like Shadertoy, experimenting with shaders is easier than ever. It was the tutorial that made me finally get past the "super confused" part of learning shaders.

It's kind of math heavy, especially once you get into 3D stuff, but I find it fun to learn, plus it's a rabbit hole and you can do some pretty cool stuff once you get into it. In general, anything technical artist related is interesting.

Another thing I'd recommend is looking into Algoraves. Algoraves are live performances where both visuals and music is performed by people live-coding their tracks and projections in some kind of language that's made for the task. TidalCycles, one of the libraries/languages that's commonly used, has a web editor, and there's also Sonic Pi, although I've never tried that one.

Processing is another language/tool used for making visual art. It also has a web edittor (with a lot of tutorials), and can make some cool visual stuff that can be fun to learn.

And one last recommendation, this time not about art, but about learning/building your CPU, your own assembly language, and learning to do stuff in it! Turing Complete is a puzzle game, where you will learn how to build your own CPU, starting from a single NAND gate, slowly combining them into registers, memory, adders, ALU, up until you have your own, complete and working CPU. You then create your own instruction set and use your CPU to solve a few puzzles.

It's super fun and engaging, and I'd consider learning logic gates and building a CPU as kind of also programming.