Excuse my ignorance, I know that 'UR' = Unrated and 'NR' = Not rated. But, what do these really mean? Does it mean that nobody took the time to rate them? That none of the ratings apply? I see some DVD that boast that this the 'unrated' version of the film, like it is a good thing. I plan to rent some DVD's to see with the family and I dont understand what 'NR' and 'UR' really mean. I dont want to see some frontal nudity or hear some bad cursing at my family gathering. HELP!!