An ancient game, older than moniters infact (there is a command in older versions that allows you to save paper on one of those old bastards that gave you a print out instad of a visual display). Made throwing sharp dwarven axes at gnomes that assault you with wicked knives and die in puffs of greasy black smoke popular. Also a test of geekness in some circles; did you play it on an osborne (I just checked this out and apparently they're making new ones, I mean the ancient things that weigh about thirty pounds and have the tiny monochrome screen; The first portable computers)? did you play it before you knew about the opposite sex? did you know the magic words (xyzzy being the most famous) before you knew how to spell your last name? did you ever play a version that only parsed the first few (I can't remember if it was three or five, I will check) letters of each word, with a maximum of two words per command? did your mother put you in front of adventure so you would learn to read (this either means that I have the worst parents in the world or the coolest, I'll consult my therapist)? These don't all have to be true for one to be a geek, hell, just knowing what I'm talking about should be an indicator.
My apologies to anyone who is offended by the way my assessment of the relationship between the geek and Adventure is weighted toward those who are at a certain point in the age spectrum of geeks. If you are simply old enough that you already knew how to read, etc, by the time Colossal Cave was available then you are by no means less of a geek. If you were born too recently, or you came to computers at a later age, you're really missing something here, check it out (I'm not sure where, but I know this game and the Zork games are available for free download, every once in a while I get a clue as to where to find them, but alas, I'm always too busy to follow up at the time... alas, woe is me)