For those who haven't yet heard, someone has been hitting en.wikipedia with what appears to be an attack looking for admins with weak passwords - "password", "password1", "[username]", etc. Then they go on a predictable spree; deleting the main page, mostly. I think we're down four so far...
It's possible someone might try this in the near future on other wikis - a lot of vandals tend to only go for en, but you never know, this one might be feeling multicultural!
This might be a good time to spread the word and ask your admins to consider checking their passwords are good and secure - after all, it's good practice anyway.