These are three websites hosting cool, fun games/challenges for programmers and maybe other IT people. I discovered them over the past year and want to share them:
https://cantunsee.space/ — I really like this one because it tests your attention to details while you’re trying to figure out which of the two screenshots is more correct. I got most of the answers correct last time I played, with maybe six wrong answers.
https://deadlockempire.github.io/ — It is a very neat game when you are a thread scheduler and need to break poorly-written concurrent programs by pausing and resuming threads at the right times. It presents an “inside-out” view on the common concurrency/threading issues and some of the synchronizing primitives — I can’t say that you’ll learn everything about them, but the game is fun. And it’s open source: https://github.com/deadlockempire/deadlockempire.github.io!
https://userinyerface.com/ — This game is shorter than the two above, but it does show some exaggerated examples of the bad user interface, and you need to navigate through them. Unfortunately, these bad UIs are present on real websites too; the most annoying ones for me are uninformative/missing requirements for password fields and bank card input fields that are so dumb that can’t filter out spaces.