I was around for the beginning of Laugh-In. There wasn’t anything like it anywhere.
… Until Hee-Haw came along. Ew! 
Eons before there was Twilight, there was Barnabas Collins and Dark Shadows.
Oh?
What about That Was The Week That Was?
David Frost, Henry Morgan, Buck Henry, Woody Allen, and the songs of Tom Lehrer (!!) (In the American version)
Political jokes, blackout skits, satirical songs, and a random series of acts. Big-name guest stars appearing briefly. Sounds a lot like Laugh-In.
All in the Family gets my vote. So much of it had never been done before, and so much of it seeped into subsequent series.
Not mentioned yet: Late Night with David Letterman, for similar reasons. I know Carson (and Allen and Paar before him) paved the way, but Letterman brought an irreverence to the format that can still be seen far and wide.
(not that I want to dis Johnny Carson; I loved, loved that show).
mmm
All That Glitters.
Mea culpa. I goofed.
Wheel of fortune
Indy 500.
Get it?! Wheels? Revolving? Revolutions!? Bwaaaaahahahaaaha…uh…ha…heh…uh…I’ll show myself out.
I agree that The Prisoner has a rational progression and you can clearly see Number 6 gradually taking the upper hand.
I watched the entire series as a college freshman on a big screen, thanks to the “Prisoner Film Society.” (The show was only 10-11 years old at that point.) I hooked in more and more people until my entire clique was with me in the audience for the last several episodes.
Smoking lots of weed helped with viewer comprehension. And most of us dropped acid before the final show: “Once Upon a Time” and “Fall Out.” You know, so we could REALLY “get it.”
What I love about this thread is that it’s like grabbing a cord and pulling, and it leads to another, and another.
I often play the game “Would this have happened if that hadn’t come before?”
Someone in my coffee joint mentioned Picket Fences, a quirky drama from the early 90s. Someone else brought up Northern Exposure. My reply? “Would these have happened if Twin Peaks hadn’t come before?”
Another comment: “I love how Kevin Spacey kept breaking the fourth wall.” Well, Danny Pudi on Community did it before that. Malcolm in the Middle spent a lot of time addressing the audience in the early oughts. As did characters on Modern Family, Saved by the Bell, and Fresh Prince.
Of course, you could argue that they were all inspired by Dobie Gillis. But would he have done it without George Burns making it a staple of the Burns and Allen Show? Or Ernie Kovacs in the 50s, who, it was said, “doesn’t have a fourth wall, he’ll schmooze with the cameraman in the middle of the bit, or he’ll bring the audience in…”
…or the Nairobi Trio.
Surprised that the Simpsons hasn’t been mentioned yet. Crazy influential.
It was a long time ago and it was too timely for anybody to show reruns of it, but I don’t remember any resemblance to Laugh-In. I wish anybody had relics of it, but there don’t seem to be any.
Stan Freberg did all those things even earlier, but he did it on radio.
There’s a BBC episode on YouTube.
You can say that about a lot of shows, including ones mentioned above—Burns and Allen, Beulah, Amos ‘n’ Andy…
If we’re doing talk shows, prior to the Smothers Brothers talk shows were inoffensive family fare, Elvis and his swiveling hips notwithstanding. Tommy and Dick pulled no punches and set the stage for talk shows with somewhat controversial and downright irreverent content that remains to this day. Ed Sullivan and early Johnny Carson would never have put themselves in a position where the network would require early episode submission so they could censor the content. Letterman doesn’t exist without them taking the hit first.
EDIT: It was more a variety show than a talk show. Still, the point stands.
It’s Garry Shandling’s Show. I had seen irreverent self-aware shows before, but not at the level of this amazing bit of nonsense.
Per the OP, when I think of a revolutionary television show I think of something that fundamentally changed the game. I Love Lucy has been mentioned and that’s a great example of a show that changed the way television was made. The show gave us the live studio audience (real laughter instead of canned), three 35mm cameras, and the rerun. For decades other sitcoms followed the Lucy model of production. Twin Peaks, Hill Street Blues, and Babylon 5 were good shows but they didn’t change the landscape like I Love Lucy did.
Naw, it was only twenty minutes into the future. 
Also a pre-Charlie’s Angels Farrah-Fawcett-Majors, as Harry’s neighbor.
Soap, for Jody Campbell. At least early one he was one of the few sane characters. And happened to be gay.
Magnum, P.I. It was one of the first detectives shows to have continuity and show character growth. The Magnum of
Season 8’s Unfinished Business is much different than the Magnum of season 3’s Did You See the Sunrise .