Back in middle school, I shared a little RPG I programmed for the graphing calculator with my friends. I called it "Arena Battle"; the game had a grinding-style combat system with 4 classes, used ASCII art for images, and had simple numbered lists for menus and dialogue options. When you had played the game for too long, a battle was triggered with the program itself; if you killed it, the game deleted itself from the calculator. If you lost, the save file was intentionally corrupted, and rendered unplayable.
After that, I got to thinking about postmodernism in game design. Metal Gear Solid provides a good example; there are a few parts of the game that are written to call attention to the fact that it is, indeed, a game... and it plays around with the player's expectations a bit. I wish there was a game that was built entirely around that sort of postmodern, self-aware design theory.
For a while after I made the calculator game, I thought about designing a similar game in QBasic or C++ that further explored that theme. It might have pitched itself as an RPG like that, built around simple turn-based Arena Combat. All the in-game menus, dialogue, and any readmes or manuals would never imply that there was anything more than the Arena. Due to what is made to appear as a glitch at some point, the character is able to walk through the solid exterior wall of the map, and suddenly emerges into something much bigger... maybe a field of garbled graphics, or something that looks like a half-completed aspect of the game that was cut at production, and progressing on to something stranger. From that point forward, it might reveal itself to be some sort of puzzle game built as a composite of several unrelated games connected by this glitch-space. The real game would revolve around exploiting intentionally-programed glitches, and the mechanics of the games themselves. It could involve manipulation of the game's files as well, requiring the user to change file names and extensions, make copies, and so on. Even in-game save menus and such could be wrapped into the designs of puzzles.
In the end, I'd want it to be something that blurs the line between the game and the medium on which it was played. I still don't know how best to go about designing something like this, but for a long time it's been something I could see through a glass, darkly.