The Hitchhiker's Guide to the GalaxyThe Hitchhiker's Guide to the Galaxy was the first adventure game I ever played all the way through. (It was text based, so I'm not certain that it technically counts as a video game.) The object of the game was to collect the four kinds of "fluff" (navel, pocket, etc.) and get to the mythical planet of Magrathea. There is a Java remake of the original text-based game if anyone cares to play.
Photo courtesy of GameSpot, a CBS Interactive site.