Need recommendations for professional, free wiki hosting

[Argy]

I want to develop a wiki that would be connected to the website of my school newspaper, of which I am currently the web editor. I don't think I can get my superiors' enthusiasm and budget behind this without first producing results. I need to find a free wiki hosting service that preferably has few or no advertisements. Can anyone recommend anything?

We use Joomla 1.0 to manage the paper's website. I'm not sure if wiki software can be uploaded directly to that...

 

[Zhen Lin]

Joomla is a fairly full-featured content management system. Is there a reason it isn't enough?

ScribbleWiki's ads seem very minimal. (It looks like even less than Bulbapedia.)

 

[Argy]

Well... the wiki I want to make is kind of like a pedia, so I would like it to be a stand-alone wiki.

For some reason I'm unable to upgrade Joomla 1.0 to 1.5, which I think is really hindering my ability to understand the software.