INFORM 7

This is pretty neat.

http://www.inform-fiction.org/I7/Inform%207.html

Inform 7 is an engine that allows you to make Interactive Fiction--like, you know, Zork and stuff. But the twist here is that the programming language is modeled around the human language.

For example, instead of something like this...

Constant Story "Hello World";
Constant Headline "^An Interactive Example^";

Include "Parser";
Include "VerbLib";

;

Object Kitchen "Kitchen";
Object Front_Door "Front Door";

Object Living_Room "Living Room"
with
description "A comfortably furnished living room.",
n_to Kitchen,
s_to Front_Door,
has light;

Object -> Salesman "insurance salesman"
with
name 'insurance' 'salesman' 'man',
description "An insurance salesman in a tacky polyester
suit. He seems eager to speak to you.",
before ,
has animate;

Object -> -> Briefcase "briefcase"
with
name 'briefcase' 'case',
description "A slightly worn, black briefcase.",
has container;

Object -> -> -> Insurance_Paperwork "insurance paperwork"
with
name 'paperwork' 'papers' 'insurance' 'documents' 'forms',
description "Page after page of small legalese.";

Include "Grammar";

You write something like this:

"Hello World" by "I.F. Author"

The story headline is "An Interactive Example".

The Living Room is a room. "A comfortably furnished living room." The Kitchen is north of the Living Room. The Front Door is south of the Living Room. The Front Door is a closed locked door.

The insurance salesman is a man in the Living Room. The description is "An insurance salesman in a tacky polyester suit. He seems eager to speak to you." Understand "man" as the insurance salesman.

A briefcase is carried by the insurance salesman. The description is "A slightly worn, black briefcase." Understand "case" as the briefcase.

The insurance paperwork is in the briefcase. The description is "Page after page of small legalese." Understand "papers" or "documents" or "forms" as the paperwork.

Instead of listening to the insurance salesman:

say "The salesman bores you with a discussion of life insurance policies. From his briefcase he pulls some paperwork which he hands to you.";
now the player carries the insurance paperwork.

Relatively easy programming! Both examples were taken from the entry on Wikipedia, by the way.