ahead of you, a cobble crawl leads down...
I've always been fond of text adventure games; I played the original "Advent" on our family's first computer, a PDP-11 my dad built from a HeathKit. When I learn a new computer language, my first project is still usually some kind of adventure game.
The genre of interactive fiction reached its commercial peak in the 1980's with Infocom's series of text adventures. The series began with Zork I and Zork II, and ran on for over sixty titles. Infocom's games were available for almost every kind of computer because they were written in something called Z-code. Z-code is assembly language for a virtual CPU called the Z-machine. Infocom wrote a single game, coded in Z-code, and then wrote a Z-machine interpreter for each platform.
Graphically-oriented games eventually doomed the text adventure game as a commercial endeavour. In recent years, though, there has been something of a renaissance in the genre. There are now many different toolkits for writing interactive fiction; my favorite is called Inform. Inform provides an object-oriented language for writing text adventures, and compiles to Z-code. There's a freeware Z-code interpreter for almost every computer platform, so an Inform-based game will run anywhere.
There's an interactive fiction archive.
Interactive Fiction Links