A while ago, I started experimenting with the idea of an interactive tour:
http://en.wikipedia.org/w/index.php?title=User:Eloquence/Tour_01&oldid=1...
Not so much a tutorial how to edit Wikipedia, but what's in there (a broad selection of content), how to use categories/portals, how the community collaborates, what Wikipedia _is_, etc.
This kind of thing would be really useful for the orientation of new staff, as a resource for autonomous exploration. But I think it would be generally a cool thing for Wikipedia (and other projects) to showcase what they are at their best.
Is there any volunteer interest in building such a thing?
I know - web site tours often suck and are kind of a thing of the 90s - but I think this could be different: it would be more of a living slideshow with captions.