Ah! The young! ;P Nethack is a single player, "go down into the dungeon, get the treasure (an amulet in this case) and escape again" type of game. Its an extension to hack, previously found on unix boxes and has been around for donkeys years. Importantly it's a triumph of substance over style... the standard version has text graphics (if that's not a contradiction). Play the game for a while and you'll never look at an '&' in the same light again ('&' is the symbol for a demon or Horseman of the Apocalypse). It's open source, so some people have developed graphical interfaces, if you're that way inclined. A commonly used phrase is "The Dev Team Thinks of Everything"... a simple one I can remember is if you try and put a potion into itself, you get the message "That's a potion, not a klein bottle". http://en.wikipedia.org/wiki/Nethack for more.