I took a quick look at the html source of a couple wiki pages, and I didn't see anything suspicious or out of nature from what I saw before. So, I would suspect one of the banner ads. That seems to be a favorite of the evil crowd these days.
Firefox + AdBlock Plus + NoScript also protects me from 99.9% of those kinds of attacks. I recommend that combination to anyone surfing the web. The site looks drastically different compared to loading in Ie.
-SK
(not declaring anything as safe, I just couldn't find an issue)