A friend pointed me to a unique form of advertising, conducted by the company AdEngag. This particular incidence was caught on the 'I am Bored' site, which practically deserves its own link if it weren't for the fact that no SEO/M I've ever run across is bored - they're all phenomenally busy (or seeking a job).

At the site, the 'hot links' ads point to several specific sites and apparently to a "Forex Money Trading" site. However, this link turns out to be just a custom Google page that has run a search for the term and is displaying Google's ads, both AdWords & AdSense from what I can see. So, Bored is advertising AdEngage which is advertising Google Ads which is advertising Forex sites. It's quite a long line and more clicks than I'd want between my site and the customers - maybe it's a rare occurrence, but it's certainly a bizarre one.