Instiki is the software that I am using to run this site, and as such I've been trying to make it do what I want. For instance, I've been integrating the bare minimum to allow easily for blogging. Here is the list of changes that I have made. You can see some of them in action on the wiki behind this site.
I am pursuing this project mainly because I think the wiki is broader and more general than the blog, and that the wiki can subsume the blog. I have tried to add conservatively to Instiki. I think it's a great project, and much of its greatness comes from its simplicity. I hope that my additions do not take away from that.
Here is a list of the features in my Instiki patches.
Blogging features
[[!include-blog-view CategoryName]]
Shows the pages in the given category in most recent order of creation in a generic blog-like view. These can be included on any page, and although my intent is for using it as a blog there are probably other interesting uses.
[[!include-blog-archive CategoryName]]
Makes the pages in a given category available by month and year, which is typical for blogs.
Added commenting facility
I added commenting mainly for the blogging feature, but it's completely orthogonal to blogging. It works on any page including blog pages and comments.
Added a preview to the edit page, which is pretty handy.
I hated having to lose context between seeing what I wanted to change and going to find it. Or similarly, wanting to see what I just changed without losing my place.
All the hot-keys, such as Ctrl-S to submit a page, now have tooltips to help users find them.
Added html export with layout
This is good for using the wiki as a content management system and still having the original wiki feel and aesthetic. I think the html export feature used to do this by default but was changed.
Here is the source code: instiki-2007-09-04.tgz
Here is the darcs repository, from which you can also browse the source code: instiki