There are some really good channels out there now. Here are some favourites:

Kurzgesagt - In a Nutshell
Explains science so, so well. There's a lot of stuff in these videos I knew from reading, but I'd never put them all together into an entirely new picture. Definite must view channel. Top quality production.


Primitive Technology
Guy in the forest (Qld. Hinterland?) builds stuff from absolute scratch. No dialogue. Fascinating viewing.


CommunityChannel
Australian lass is funny without resorting to jokes about her vagina. Doesn't even swear (I think). Kids' favourite.