The role play video game (RPG) Never Winter Nights is not only a wildly popular game to play but also enjoys a large community of user-developed enhancements to the game. This is made possible because of the Aurora toolkit BioWare includes in the game. This toolkit provides a user interface comparable to many popular 3D design tools such as AutoCAD, Maya, or Unreal Editor and allows the developer/storyteller to craft their own scenarios using the same technology that drives the NeverWinter Nights game.
The BioWare website provides some information about the tool for builders and describes its capabilities. There are also a number of tutorials on the web about how to use the toolkit. These include creating custom worlds or levels, changing the appearance of in world characters, customizing the triggers and rules that govern execution of the game, introducing your own multi-media assets (graphics, sounds, etc.), and developing your own stories or plots.
Using these tools is relatively easy and so much so that they have moved beyond the domain of technical enthusiasts. They have been used by children as well as adults, fine arts majors as well as engineers, and used to study various "soft" topics such as the role story-building plays in the self-esteem and teamwork of children.
While the toolkit and some of the tool skills are similar to other tools (such as Unreal Editor) the tool is clearly tailored to what is required by a role-play, story-driven or plot-driven experience versus what is required by a "shooter" game. As a result, the appeal of the NeverWinter Nights Toolkit relative to alternatives depends upon the experience you are attempting to create.
For example, Aurora puts less emphasis on the physics engine than in the typical shooter game toolkits but gives more emphasis to scripting dialogue. The as-provided library of weapons is much more modest but there it is easier to support a world of autonomous non-playable characters (NPCs) as a supporting cast to your story.
An example of a "serious game" built with Unreal (and not NeverWinter Nights) is HazMat developed by Carnegie-Mellon for the Fire Dept. of New York. For this simulation, Unreal offered an attractive level of customization. This is a facilitated simulation so a strong story-line to drive the events isn't necessary. In fact, since the purpose of the simulation is to allow fire-fighters to experience an unfolding hazardous materials crisis in an unstructured, but safe, manner - a story line driving the simulation could be regarded as undesirable. Unreal also provided the Karma physics engine which is valuable for flames, flying debris, gases, etc.
Compare HazMat with some of the simulations developed for the U.S. Army to tell the story of certain events or simulations developed for the Dept. of State to socialize diplomatic trainees to national customs. In these cases, a strong story is necessary. The needs of the simulation parallels to role-play games and these have been more suited to the advantages of what is available in NeverWinter Nights.