I’ve got over a thousand in Space Engineers, although some of that is from leaving it on overnight to refine materials. Or possibly exiting the game, but forgetting to actually leave the main menu. Does Steam track time when the computer is asleep?

But I’ve likely got close to ten times that number in Dwarf Fortress. I’ve been playing it off and on for close to a decade and a half now, and when I get into it whole days can just fly by.