Adventure: Colossal Cave (Crowlther and Woods, 1979 or 1980)
One of the first (if not THE first) adventure games, Adventure was little more than a treasure hunt game in which the player would solve puzzles, navigate mazes, gather up valuable items, and drop them off in a building, all while killing a few dangerous monsters that got in the way. Though it didn't have much of a plot, the game did have some good descriptive prose and was quite funny in a few places. The biggest disadvantages of the game were its extremely limited parser and memory capacity which probably account for its lack of importance and popularity when compared to the much similar Zork I released soon after. Still, Adventure is worth playing today for the nostalgia and for the fact that well-designed games never do go out of style.