The Internet Archive is the ultimate 'I'm bored' killer for a curious kid, provided you're okay with them having the keys to the entire history of human media. It’s a library, not a playground, so it requires a level of maturity and intentionality that most 'kid-friendly' sites don't ask for.
If you want your kid to stop scrolling and start exploring, this is the place. Just be ready to sit beside them—partly for safety, but mostly because playing Oregon Trail or Prince of Persia in a browser window is still a blast.

