I was tricked into writing a VM while doing Advent of Code last year and it really deepened my understanding of programming (e.g., on how to implement simple coroutines).

Advent of Code is supposed to be 25 daily programming puzzles leading up to christmas. I went in thinking they were going to be algo/datastructure tasks but half of them were actually about implementing and using a VM for a made up assembly language! The difficulty ramp was gradual enough that I did it with no background in compilers and it was lots of fun.

If you want to experience it, in last year's version https://adventofcode.com/2019 you write the VM in Days 2, 5, 7, 9 then apply it to solving problems in Days 11, 13, 15, 17, 19, 21, 23, 25.

I ended up loving the VM puzzles and ended up doing the AoC author's other challenges which have a similar theme: https://challenge.synacor.com/