Advent of Code is an Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like. People use them as interview prep, company training, university coursework, practice problems, a speed contest, or to challenge each other.
You don't need a computer science background to participate - just a little programming knowledge and some problem solving skills will get you pretty far. Nor do you need a fancy computer; every problem has a solution that completes in at most 15 seconds on ten-year-old hardware.
If you'd like to support Advent of Code, you can do so indirectly by helping to share it with others, or directly via PayPal or Coinbase.
Please thanks the author Eric Wastl who also made Vanilla JS, PHP Sadness, and lots of other things. You can find him on Twitter and GitHub.