Authoring Systems

CMU SCS OZ Project
Develops technology and art to help create high quality interactive drama. This especially means building believable agents in dramatically interesting micro-worlds.
http://www.cs.cmu.edu/afs/cs.cmu.edu/project/oz/web/

Interactive Fiction Authoring with IFML
XML-based Interactive Fiction Markup Language (IFML) used to create text adventures that run in your browser. Includes a sample game with IFML code, documentation, tutorials, downloads, mailing list, and a forum.
http://ifml.sourceforge.net

Interactive Storytelling Tools for Writers
Software for creating and using interactive storyworlds.
http://www.erasmatazz.com/

Sludge
SLUDGE (standing for Scripting Language for Unhindered Development of a Gaming Environment) is a system by which anyone (within reason) can make an adventure game.
http://www.hungrysoftware.com/#/tools/sludge/

The Unofficial World Builder Home Page
Downloads, faqs and links to worlds built with this engine. For Macintosh.
http://we.got.net/~mapman/wb/

Visionaire
Use Visionaire to create a complex adventure game without the need of any programing experience. This site offers information about how to use the software and what you can do with.
http://www.visionaire2d.net/index.php?newlang=english

Wintermute Engine
Wintermute Engine Development Kit is a set of tools for creating and running graphical "point&click" adventure games. The kit includes the runtime interpreter (Wintermute Engine, or WME) and GUI editors for managing and creating the game content (WME tools) as well as the documentation, demonstrational data and prefabricated templates.
http://www.dead-code.org