It seems that Google AdWords' new Quality Score feature has a bug, and that are driving cost-per-click prices on certain keywords through the roof. As Search Engine Land reports:

Many are seeing high quality ads and keywords hit with incredibly high CPC prices overnight. Google replied to several advertisers telling them they are aware of the "temporary issue" and "they are working to resolve it as soon as possible."

Well, while PPC advertisers should very much hope that Google is looking into the issue, this isn't the type of thing that you'd expect from a such a leviathan such as Google--mind you, if anyone can get away with it, it's them.