The
logical thing to type when
Infocom's
Zork would warn you against being eaten by a
grue. Doing so would prompt the
game to
explain what the
hell a
grue was. Now if I remember correctly, for a long time you could ask this of ANY
Infocom game and it would still tell you, regardless of whether the game contained
grues or not. For some reason my friends and I thought that was really
cool.
Of course, back in the day, a game that allowed us to manipulate a little square carrying a big arrow for a sword which it used to kill ducks totally impressed us.