When something is past the point of simply "ridiculous" but does not quite merit being referred to as "rigoddamndiculous"
Also this word can be used as a less-profane way to say something is "rigoddamndiculous" for those who are concerned with avoiding blasphemy but still want to define something as being safely beyond simply "ridiculous."
Student 1: Dude, how's your workload this semester?
Student 2: I have 21 credit hours and a 20-hour-a-week job.
Student 1: Woah, that's rididdledamndiculous.