Drift, not quite buddy...
Jonny, something like this??

How long has it been going on for??
As far as I can make out, it's an advertising thing as rubiconproject.com is a genuine ad agency type setup that various websites use. FOG has no adverts, but I would guess that another site you frequent uses them to serve adverts, and something's gone wrong somewhere.
I don't think it's anything nasty, just annoying until it gets sorted.
I'd normally recommend installing AdBlock as a matter of course for web use, but you could just tell your browser to block that domain.
I f you're running Internet Explorer though, you should be able to click on "tools" in the menu bar, then Internet Options, and then the Content tab on the box that shows up, and there's a content advisor which you can turn on and enter addresses of websites you want to block.