The slogan used by NBC to describe their Thursday night lineup of comedy (and one drama). Considered the biggest night in television ratings, the 2 hour period between 8pm and 10pm (and now extended to 3 hours and 11pm) usually contains the highest price for commercials in the entire week (except for special events and sporting finales).
Before the slogan was born, NBC had already established itself on Thursday nights because of one show: The Cosby Show. From when it debuted in September of 1984, until it moved to Saturdays in July of 1992 (and had its finale in September of 1992), it owned the 8:00pm Thursday night slot. It was hugely popular and anything that was thrown up against it would often crash and burn.
Unbeknownst to most people, the second part of the Thursday night NBC juggernaut had already been on the air for 2 years, but hadn't gotten a good lead in until The Cosby Show established Thursday night for it. After going through a couple of years of terrible ratings, Cheers finally caught fire and became a massive hit as well, dominating the 9:00pm slot.
The third part of the early Thursday lineup on NBC was at 8:30pm was Family Ties. While it only existed in the Thursday lineup from January 1984 to August 1987 (with stints on Wednesday before that time and Sunday after), it too was a hit (although I'm sure the Cosby lead in helped a lot).
Finally, the 9:30pm slot went to Night Court. This wasn't a permanent fixture, as the popular show was moved in and out of the Thursday lineup, but was in place for the early part of the NBC domination (May 1984 to March 1987).
This was considered the early golden years for NBC on Thursday night. The strength for NBC was that they would rotate new shows into the Thursday lineup when the old ones would become stale, and other networks were powerless to stop them (or didn't even try).
Unfortunately for NBC, the powerhouse that was Thursday has slowly started to lose its strength and stamina. While the original lynchpins of Cosby and Cheers gave way to Friends and Seinfeld, the middle shows (8:30pm slot) were often "whatever sticks to the wall" material. Such dreck as "Jenny", "The Single Guy", "Jesse", and "Suddenly Susan" were diluting the power of the Thursday lineup. Propping up the lineup was the addition of the drama ER at 10:00pm. Now NBC had a definite 3 hour bracket, with the second golden years being from 1994 to 1998 as Friends, Seinfeld and ER completely dominated the Neilsen ratings, often battling for the #1 spot among themselves.
The current lineup is a pale comparison to the early NBC juggernaut and even the 1998 version (as of 01/01/2001).
What makes this even sadder is that the two bracket shows with the highest rating are very close to ending their runs. The Friends cast has become 30somethings and most of the major characters from ER's glory days have moved on. The shows in the middle are definitely not going to be able to carry the night on their own. Add in the fact that CBS has decided to kick NBC while its down by running its wildly popular sequel to ratings smash Survivor (cunningly called Survivor 2 : The Australian Outback) in the 8:00pm slot, and that ABC runs an episode of the game show smash Who Wants to be a Millionaire on that night, and that even UPN gets into the act by having its demographic champion WWF Smackdown on at 8:00pm, and NBC's hold on Thursday might be gone. Quite simply, there might not be a Must See TV anymore.