Take skull
Lately, I’ve been heavily interested in Interactive Fiction.
Remember the Hitchhiker’s Guide to the Galaxy ? It’s a full text game, based upon the (in)famous Scott Adams SF novel, that I advised you to play at the office (no graphics, no sound, a small DOS window) a couple of days ago. It goes like this (what I typed is in red) :

You wake up. The room is spinning very gently round your head. Or at least it
would be if you could see it which you can’t.
It is pitch black.

>open eyes
They are.

>turn light on
Good start to the day. Pity it’s going to be the worst one of your life. The
light is now on.

Bedroom, in the bed
The bedroom is a mess.
It is a small bedroom with a faded carpet and old wallpaper. There is a
washbasin, a chair with a tatty dressing gown slung over it, and a window with
the curtains drawn. Near the exit leading south is a phone.
There is a flathead screwdriver here. (outside the bed)
There is a toothbrush here. (outside the bed)

>take screwdriver
You can’t reach it from the bed. The effort almost kills you.

>stand up
Very difficult, but you manage it. The room is still spinning. It dips and
sways a little.

Well, it’s what adventure games have been through the 80s with a lot of success, when computers couldn’t easily handle graphics and not everybody had a mouse.
I’m fascinated by these games. The power of imagination is enough to make you live wonderful adventures, solve tricky puzzles, travel very far geographically or chronogically. No restriction due to the cost of designing a 3D animation, for example. And the limitation of the text interface actually is an asset an author can play with (see all of Raymond Queneau’s works).
Moreover, by searching around on the web, I found that this type of games, called Interactive Fiction are still being played and created by a lot of passionate people around the world ! There’s even an annual competition where authors present their games (of an unbelievable quality), which are scored by players.

Actually, the main resource is this FTP site : ftp://ftp.gmd.de/if-archive (with this mirror for North-American folks : The IF Archive).
This german server archives exhaustively everything that has been done since the beginning of Interactive Fiction, and every serious author upload his game(s) here when it’s released (for free, obviously !)
Add some online newsletters with reviews and author interviews, and two active and civilized newsgroups : rec.games.int-fiction for players and rec.arts.int-fiction for writers, and you’ll get the current dynamism of the genre.

And the most seducing part of it, as far as I’m concerned, is that anybody can write his own IF games, and that the systems to do so are freely available on the net : TADS, Inform and a lot of others, along with free tutorials, extensions etc…
[I’m a bit technical here :] The wonderful thing with these systems is that they provide the parser, the part of the program that analyse and understand your sentence (« take screwdiver », « look under bed »), which would be a hell of a task to develop. These systems generally feature a compiler, to transform your scenario into a cross-platform playable game, and an interpreter, to play this generated game. The beauty underneath is that the game you design (what I call the « scenario ») is written in a dedicated object-oriented language, extremely easy to learn when you’ve already coded in Pascal or C/C++. Look at this TADS example, pretty self-eplanatory :

cave: room
   sdesc = « Cave »
   ldesc = « You’re inside a dark and musty cave. Sunlight pours in from a passage to the south. »
   south = startroom
;

goldSkull: item
   sdesc = « gold skull »
   noun = ‘skull’ ‘head’
   adjective = ‘gold’
   location = cave
;

With these few lines of code, we have created a cave where the player can go, that he can leave (« go south »), look at (the ldesc part), and refer to (« leave cave »), plus an object in this room the player can look, take, drop, and refer to in many ways (« take skull », « pick up gold head », etc…).
Now you just begin to see the offered possibilities.
[End of technical part ; Dad, you can read again from now]

What these people do is wonderful. Plenty of terrific games are released each year, I’ll keep you in touch.