Used to be Skyrim. On a road trip, I once explained the entirety of the assassins' guild ("Dark Brotherhood") quest line to my wife, who is not a gamer. In detail. With dialogue choices, storyline choices, what happens if you do X, what happens if you do Y, full spoilers, where it ends up, who betrays whom, all that good stuff.

We were bored.

I've also explained, at length, exactly what Enderal is. In short, it's a mod for Skyrim, but it's also a whole new game that takes the game engine and some of its assets, but has you create an entirely separate character, uses separate saves, is set in a whole different world you cannot reach from Tamriel (the world space of Skyrim and the country Skyrim is a province of) and vice-versa, and uses elements from Skyrim, Fallout (specifically, radiation), and their original world. It's basically a game within a game. It became infamous as the revered "Skyrim grandma" Shirley Curry tried it, and rage quit because it was too hard, and everyone loves her. She's even been confirmed as an NPC in Skyrim's sequel. (It's not that hard if you're a seasoned gamer. But Curry is an octogenarian grandmother, and Skyrim is an easy game that she enjoys live-streaming casually on social media. No one who knew Enderal should have recommended it to her. That's entirely on them.)