Nethack

A video game. An evolution of an earlier game called Hack? which was itself an evolution of the much more famous Rogue?. Nethack was developed "over the net", hence the name. Played using a text-only graphics (in a manner similar to ASCII art). You took the part of a dungeon delving hero in search of the [Amulet of Yendor]?. You quest was played through several randomly created levels each containing many many monsters, items, and magical artefacts. Your character was initially accompanied by a pet cat or dog (which you could name). Unparalleled in scope, hundreds of scrolls, wands, potions, rings, weapons, armor, food, lockpicks, and monsters that almost always had an interested interaction if anyone had thought one up. Some interactions (and bugs) were rare and occasionally amusing.

"You fall into a spiked pit. The spikes were poisoned! I'm afraid the poison was deadly... You die."

The following is a sample from a typical game session, to show how the "graphics" look like:

                    -----
                    |+..|      ----------
                    |....######..........######### -----
                  ##....|      |..<.....|         #-..)|
                  # |...|      |.?......|         #|...|
         -----  ### --|--######.........+#        #+...|
         |....| # #############-.--------#      ###---.-
         |.?...##                        #      # #
         |....|                          #    ### #
         -----                         #####  #   #
                     -+-------------    #--.--#   #
                     |..@...........### #|....# ###
                     |..........d..|  # #....|  #
                     |........$.....#####|...|  #
                     ---------------    #+.$.|
                                         -----

Apart from the original text mode, there are interfaces that replace the characters with small images, e.g. instead of "?", a picture of a scroll is shown. Another variant, Falcon's Eye, offers a pretty isometric? view of the dungeon map.

There was a commercial version called Dungeon Hack with a first-person view, but it left out many of the little features that make Nethack worthwhile even after years of playing.