I'm getting that too. Since it's a wiki-style site, it could be that some rude anon decided to plant something, and it was reported to Google enough. Or it could be something stupid planted in their ads too, that's always a possibility. I'm sure that the admins are working to fix everything asap, so it should clear up in a few days...

EDIT: Yup, I'm poking around and it's something in their ads.