There is something really wrong/different about how Google is matching ads to certain pages. A major change must have been made in the last 2 weeks.
One of my sites is about auctions. People come in via searches such as "car auctions in denver". The ads on the first page are very relevant. Most people click to the page on individual car auctions and now the ads are not relevant at all. Now the ads are about printers and online degrees. Most people also now start to look at individual car pages and now the ads are about dishwashers and stocks.
14 days ago all the ads on the flow I just described were contextually relevant. What a mess. CTR and CPC both are all-time low as a result.