How about a "share a glimpse into your world" week?
If you've asked questions here it's probably because you have a project -- maybe a full-on novel/game/script/etc you're in the midst of, or maybe a more early-stage idea. Either way, would people be willing to share a (non-contract-voiding, non-copyright-constrained) bit of what you're doing? A drabble (very short writing), a scene, a short story, a setting description, a sketch or painting... something that shows a little bit of what you're doing with your worlds?
If people like this we'll figure out how to do it in a way that's consistent with site structure. I'm envisioning a meta post with links to material elsewhere, so you can host (and control) it yourself. If you don't post it directly on SE then it's not subject to the CC-BY-SA license, which has been relevant over on Writers with some "share your work" projects. But I'm open to other ideas for structuring it, too.
There's been a lot of discussion in comments (thanks!) about implementation. If we could get a BlogOverflow blog that'd be great, but SE might not allow it (see the linked post). If not, and given that the content might vary widely -- short text pieces, hundred-page reference documents, drawings, videos, things I haven't thought of -- I think people should post their material wherever it makes sense and we'll make a nice meta post with links to all of it. That way it can be on your blog, in a Google doc, a GitHub repository, a Vimeo link... whatever works best for you. The downside is that it's harder for users here to provide feedback (since it won't be posted here), so I'd encourage you to do it somewhere that allows people to comment, but that's up to you.
Followup: Post links to your work on this meta post. This is a staging area, not the final collection; someone will later take all this and make a blog post and/or meta post to tie it all together.