Inform 7 was recently released. It completely re-makes the language as a natural-language programming environment. It can still be found at http://www.inform-fiction.org/. Graham Nelson is still credited with creating the language, Andrew Hunter and David Kinder are credited with creating the UIs, and Emily Short, Andrew Plotkin, and Sonja Kesserich are all given a degree of credit as well.
"An Example" by Kirk McDonald
An Empty Space is a room. "Around you is an empty room, with plain white walls and a tiled floor."
That is an actual example of code. It defines a single room, with a description that it prints out when the player types "look." More lengthy and useful examples can be found on the website. The first one I read can be found here, and is highly impressive.
Where code written in previous versions of Inform was largely composed of inline object definitions, code in Inform 7 contains many assertions. "An Empty Space is a room" is an assertion. Expanding on our source text above:
A pedestal is in the Empty Space. A stone is on top of the pedestal.
Where before one would probably say something like:
Object -> pedestal "pedestal"
has static supporter;
Object -> -> stone "stone";
When "played," this example yields:
Around you is an empty room, with plain white walls and a tiled floor.
You can see a pedestal (on which is a stone) here.
You are carrying:
As this version is still very new, I haven't yet had a chance to play with it much. (I also haven't played with any version of Inform in several years.) However, what I've seen so far is very promising. It naturally can still compile to the venerable Z-machine format, although by default it uses a newer "blorb" format. This format is a wrapper around the Z-machine format that allows for the storing of additional metadata.