Yesterday, I nuked the wiki database and restored (most of) the articles from backup. This takes care of the remaining spam and reduces the database size considerably. As a bonus, I did some updates to the website layout and the various themes (forum, tracker, wiki). Wiki account creation has been disabled, if you're interested in editing, contact the development team, and they will create an account for you.
The next step is to merge all the game-related information from the website's Documentation section into the wiki,
and replace it with a simple About section. While this is mostly a technical issue, a documention cleanup has been long overdue. Maintaining three sets of documentation (source tree, website and wiki) is too much of a hassle. The wiki should be the master source for documentation and the source tree itself should only contain a README and INSTALL instructions. The website should only offer information about the project itself and link to the approriate wiki articles.