Starts off fairly easy, but quickly just becomes ridiculous. I've only gotten about 14 steps in so far.
Pointless sites is a great conglomeration.
I think there's one called sand spiel? It's a fun physics toy.
Also can't go wrong with Simon Tatham's puzzle collection.
https://neal.fun/deep-sea/
The website shows the depth of the sea. It takes a really long time to get to the bottom
Anything on neal.fun is great
My kids are gonna love the size of space one
You just made me realize that there's other stuff on the site. I know what I'm doing for the day
Here's the same thing for space!
If the Moon Were Only 1 Pixel, A Tediously Accurate Map of the Solar System
https://joshworth.com/dev/pixelspace/pixelspace_solarsystem.html
Oh dang that's a pretty good one. Good find
Just went through the whole thing. That’s incredible. I had never heard of most of those animals.