Emily Short is trying something very exciting in interactive fiction design: she’s written a conversation system that lets you write in new dialogue. It’s supposed to ask you how that dialogue should fit into what’s already there, then generate some Inform 7 code. You send her the code and she incorporates it in a new release of the game (probably with some tweaking, since she’ll be getting other updates at the same time).

Here’s the first announcement, and an update. Sadly I have no time to play with this, but the idea is fantastic.