As for things that seem absurd to my kids...
Certainly not playing outside. They did that, and kids still do that in our town, running from door to door in the neighbourhood. When I went to the corner store this morning, I waved at a neighbour's little boy, who was out shooting pucks at a net in his driveway.
Not records or corded phones, either, as we still have a landline and my son and his friends collect records (which continue to be released). And both kids can use a stove and other kitchen appliances (really, the microwave isn't very good for actual cooking).
But, I do think they do find it hard to imagine not being able to Google an answer to any question that occurs to them, the moment they think of it. They find it strange to think of having to write physical letters in order to stay in touch with absent friends, and then have to wait weeks for a reply. They're used to being able to reach out to almost anyone, anywhere, at any time (except for Grandma, who doesn't have a cellphone).
While my kids did play with my old typewriter, I think they would find it hard to write an essay for school on it. They're used to being able to move chunks of text around, and look things up on the fly, and have all the research they need right at their fingertips. I'm sure they've never used White Out/Paper Mate - or even more Old School, literal cutting and pasting, with tape and glue.
I'm not sure they know how to use card catalogs, either, as all the libraries are organized digitally now, and searchable online.
One of my son's university classmates HAS deliberately chosen not to have a cell phone, or even a landline - my son is very irritated about this, as it makes it difficult to coordinate with him for projects.