Once, when I had a lot of time and nothing to do, I played Zelda in an emulator and took snapshots of all the overworld screens in this classic Nintendo game. I carefully removed the guy from each screen and then stitched them all together.
This is a map I made of the complete overworld of King's Quest I. This is the original version, not the updated version that was released years later.
The classic game Adventure includes a maze where all rooms have the same description. Stumbling through it can be really frustrating as leaving a room in one direction doesn't necessarily mean you can come back in the opposite direction.
I mapped the whole thing a few years ago. After playing around with it for a while I found that I could lay out the whole maze without one-way paths or crossing paths or anything like that. More recently I decided to typeset this as a project to learn the basics of MetaPost (a language for generating figures).
My map is below; click on it to get a PDF version for printing.
Wraith is a little-known game by John Carmack written for the Apple II series of computers. I figured out the format he used to store maps and tiles and generated a complete set of maps for the game, including all monsters in their original positions. Here's a sample map:
Click here to see all of them.