21. You definitely waste some hours on https://sandspiel.club/
22. Interesting one http://adarkroom.doublespeakgames.com/
You wake up in a dark, freezing room. Stoke the flames.
23. Neopets 🙂
24. Here is Sporcle on which I could spend days on end trying to play all the quizzes available.
25. This sucks you in http://www.flashbynight.com/drench/
26. Google Maps. People don’t seem to realize how crazy it is to be able to see literally the whole planet. If you showed this to a person who lived 50 years ago, they’d be amazed. I have spent entire evenings just scrolling across distant countries, checking out villages in the far east of Russia or some desert in Mongolia, clicking on random landmarks and using Wikipedia to learn about random places. It made me realize more how many people actually live on this planet and how big it is. As a European, I noticed that the Alps are actually not that big. There are lots of mountain ranges with much higher mountains in them that I guarantee you have never heard of. I think it is an amazing tool that can really give you perspective. People use it in their daily life to find the nearest Starbucks, but it is much more than that.
28. Go through https://www.moviemistakes.com. A lot of inconsequential stuff but a lot of things so obvious you’ll wonder how you ever missed them.
29. This site The Wiki Game is a pretty good one. The objective of the game is to start at one Wikipedia page and race against other people to a completely different Wikipedia page by clicking on links to different articles. You could definitely spend at least an hour on it.
30. Test your brain with number memory, reaction time, verbal memory, visual memory, hearing and typing speed.