Discussion on a Wiki Page
I'm in the process of building a SharePoint community within the company I'm in, and I'm being aided by Ting Fong, one of the bright chap I had the pleasure of training, and microlau, my friend and colleague whom I'm sure you are no stranger to. He is working on enhancing the forums, to be able to mark a post as answer, as well as rating the thread.
While he is working on the forum, I am working on the wiki, to provide the ability to have a threaded discussion on the wiki page itself. Yes, I am also involved in CKS:EWE, but the features in EWE doesn't meet my needs.

The above shows a screenshot of the customisation I did. It is using a OOTB discussion list to store the threads, and have no problems with using other discussion lists that maybe introduced in your enviornment via CAML. What this little pet project has acheved are the following.
1. Able to limit your customisation to a single wiki page in the entire farm, something Mark Miller is trying to achieve.
2. Able to bring the context menu of the content type into any SharePoint page, not fully tested since I haven't added any new custom menu into the content type, but the context menu is showing and working fine!
Lets hope I can find time to document this soon!
P.S., the controls you see in the screenshot, the RAD tree view and RAD editor is Telerik's new ASP.Net AJAX controls. Very easy to use, considering someone who has never touched AJAX before!