The time period on Australian television when the Nielsen boxes inexplicably get ignored by commercial networks, and the public is left with the most execrable content that television has to offer.

Before the black box of the Nielsen Ratings System, there were three or four ratings periods per annum where selected families would fill out log books of their television viewing habits. The media would program their blockbusters and popular content accordingly. These ratings periods were generally set around Christian holidays, with the two weeks over Easter and two months over Christmas set aside as non-ratings periods. With the onset of electronic surveillance the importance of log books diminished and ratings could be collected instantly. Yet in the land Down Under, non-ratings period remained. And it wasn't due to devout Christianity

Given that the media are a business and not a public service*, having a periods sans-ratings is hard to explain. Apart from the ability for the networks to give their stable of personalities a summer holiday, non-ratings period is probably more pronounced in Australia due to legislative provisions that require mandatory Australian content on commercial television. To summarise, the Broadcasting Services (Australian Content) Standard 1999,

Whilst the standard does state that Australian content must not simply be relegated to timeslots better used for phone sex advertising, it doesn't specify that the content needs to be shown in ratings periods. As a result, commercial stations produce dirt cheap Australian programs, and show them when they won't be rated. To fill the gaps between the Australian shows, most networks run endless reruns, and the content that even America rejects. The Bette Midler Show, anyone?
* - Apart from the Australian Broadcasting Corporation, which is a tax-payer funded public service....1 cent a day for independant media!