yep they are called it or itx fares. Airlines offer them usually for the entire season. In peak season they can be cheaper than the published ones. However in off season they are usually a bit more. They have to be sold with another travel component - either a car or a hotel.

I've booked trips to the US many times using these to visit the in-laws. Usually via lastminute.com in the UK coz they offer the ability to only book one night in the hotel even if the tix length is 2 weeks or so. It can be much cheaper to book it that way than the published fares available. I never show up at the hotel!