Perhaps the best example has been a native macOS app that is a completely custom text editor with built-in debugger, lsp support, fuzzy finder, etc stuff you'd expect. Inside the same app is a library of books i can read within the app completely formatted and for every chapter/section of each book that is a quiz to take (LLM generated of course), a "recitation" tab where i am asked a question and say outloud my response to the AI to evaluate me on and then finally practice problems to do within the custom text editor (these are usually programming books). The reader also has ai re-write built in.
As neat as this is, and i worked through K&R like this, i have ultimately fallen back on "just read the damn book and go to the AI when you've got questions."