Adventure games have a long and storied history interwoven with the history of computer entertainment. Starting in 1974 - the same year as pencil and dice game "Dungeons and Dragons" was first published - dungeon-crawl type games began to appear on college mainframes. System resources were limited in those days, and administrators would often delete games out of hand. The game pedit5 was an excellent example of this. You can tell by the filename that it masqueraded as a text editor program.
Following on the heels of pedit5, was dnd, also released in 1974, but in a programming space that allowed it to exist as a game. It continued to be supported and developed on the PLATO educational system until 1985. It continues to be played to this day.
In the summer of 1979, high school student Richard Garriott (known to his friends as "Lord British" due to his accent) programmed in BASIC his 28th dungeon computer game, dnd28b, released as Akalabeth. At first, he created it solely for his own enjoyment, then sold it himself in ziploc bags at the computer store he worked at. Later, in 1980, the game was published by a software company. Akalabeth (named for an Atlantis-like land in Tolkien's The Silmarillion) was very much a template for all of Garriott's later Ultima games, and the rival series Wizardry.
Rogue has probably spawned more descendants than any game to originate on a computer, (other than perhaps the hugely influencial mainframe arcade game Spacewar). So many in fact, that a new adjective was created to describe games in the genre: "Roguelike" games. The game was originated by two students at the University of California Santa Cruz in 1980. A third collaborator soon joined them, and eventually development of the game moved to another school along with two of the programmers (who then joined forces with another.) The game has been ported to almost every computing platform in existence, including the PalmPilot. The basic characteristics of a Roguelike are simple - Make your way to the bottom of a randomly generated dungeon, battling randomly placed creatures along the way, getting randomly placed better equipment and magic items, and leveling up (increasing your abilities and hit points). It's a simple formula, but the turn-based games of the early 80s directly inspired later blockbusters such as Diablo. What was great about Rogue was it was a different game every time - the creators wanted to make a game that would be fun for them to play, too, and could surprise them. And I'm sure it has!
Gamasutra article on Rogue (with some comments from the programmers at bottom)
Temple of the Roguelike
DiabloRL, a Roguelike based on Diablo (which itself was inspired by roguelikes)