"That Was the Week That Was" first appeared in the US in a special edition that was a memorial to John F Kennedy after his assassination. I believe that was the original British cast, but the show stimulated an enormous amount of interest in what they were doing over there, so an American version appeared the next year.
It was topical. It didn't pull its punches. It was sly, most Americans' introduction to "British Humor," more than a step up from Jerry Lewis, and it moved quickly. Its was urbane, a style that David Frost came to symbolize, although the conspicuous consumption lifestyle he developed was really something else. Perhaps he became what he started out to mock.
It's surprising it's gotten so little attention, as it was widely regarded a direct inspiration for "Rowan and Martin's Laugh-In," and it is surely not chance that the decades old American comedy show's weekly announced name isn't "Saturday Night Live," but "Saturday Night." Surely a tip of the hat to TW3's original name.