'The Muppet Show' debuted in the UK because it was rejected by every US network.

Jim Henson and his Muppets were part of the first season of 'Saturday Night Live' because NBC was hoping to tamp down Lorne Michaels' countercultural plans for the show.

Before 'The Muppet Show,' Jim Henson produced slapstick coffee commercials featuring the puppets.

Watch episodes of 'Sam and Friends,' the earliest show featuring the Muppets.

Jim Henson's 'Fraggle Rock' was the first American TV series to air in the USSR.

Jim Henson and his creative team constructed several optical illusions to make the Muppets appear as though they walked through the real world.

Jim Henson's 1986 film 'Labyrinth' was initially a commercial failure in the US, though it slowly gained an audience that now considers it a cult classic.

Watch Jim Henson explain how to make a Muppet.

Fascinated by the 1960s counterculture, Jim Henson tried to build a psychedelic nightclub.

The Beatles' appearance on 'The Ed Sullivan Show' in 1964 launched Beatlemania in the US after the band struggled to break through to American audiences.

The Beatles were not an immediate success in the US—their label rejected their first two singles, and the band was mocked on the TV show 'American Bandstand.'

Dolly Parton hosted two separate variety television shows called 'Dolly.'

'SNL' began as a low-budget replacement for reruns of 'The Tonight Show'

Johnny Carson, host of "The Tonight Show," asked NBC to move his reruns to weeknights instead of weekends. That freed up a weekend slot and the network decided to try a new live show.

Spinal Tap began as a sketch on a short-lived TV show

The fake band might be best known for "This is Spinal Tap," 1984 movie that effectively created the comedy mockumentary, but the premise began with an appearance on a short-lived ABC show called "The TV Show."

Tracey Ullman sued 'The Simpsons' after the cartoon left her show

The legendary and long-running animated show debuted as a series of shorts on "The Tracey Ullman Show" in 1987. Years later, after a standalone "The Simpsons" series became a breakout success, Ullman sued 20th Century Fox, the show's parent company, claiming she was owed royalties for merchandise based on the show.

'SNL' was originally called 'NBC's Saturday Night'

Another show already owned the title: the short-lived "Saturday Night Live with Howard Cosell." The variety show only lasted one season and was widely panned, despite featuring several talented comedians—like Bill Murray, Christopher Guest, and Billy Crystal—who'd later be stars on "SNL" ... after officially changing its name.

'Sesame Street' was once removed from television in Mississippi for being too controversial.

Check out one critic's guide to the best Muppet movies, including 'The Great Muppet Caper,' 'The Muppets Take Manhattan,' and more.

Memos detailing the shows David Attenborough commissioned, including Monty Python

From 1965 to 1972, Attenborough was on a trajectory to become the BBC's next director-general while serving as Controller and Director of Programs, overseeing what would air on television. "Monty Python's Flying Circus" and "Pot Black," which popularized the cue sport of snooker in the UK, were among the eclectic mix of shows he commissioned.

The American 'Who Wants to Be a Millionaire?' redefined the quiz show

The show was already a success in the United Kingdom when it was adapted for the US to boost ratings during 1999’s “sweeps week,” a pivotal time for television ratings. The show worked, thanks to a charismatic host in Regis Philbin and the high stakes of a big cash prize. That combination would be replicated with great success in reality competition shows, such as “American Idol,” which would follow.

'Ted Lasso,' the Apple TV show about an American football coach managing a British soccer club, began as a series of promotional videos for NBC.

Before he had his own show, Pee-wee Herman appeared on 'The Dating Game'

Paul Reubens' character Pee-wee Herman would become a sensation with his 1986 children's show "Pee-wee's Playhouse," but in 1979 he appeared as the hilariously naive character on "the Dating Game." It's not clear if the show (or its audience) understood what they were seeing.

Michael Nesmith, an original member of the '60s group the Monkees, created a music video show that inspired MTV.

SNL's history in 60 seconds

Saturday Night Live has been a fixture of American comedy since 1975. Created by Lorne Michaels and Dick Ebersol, the show was designed as an alternative to late-night reruns, blending live sketch comedy, political satire, and celebrity impressions.

Auditions for the US adaptation of 'The Office' included many now-famous actors

When NBC decided to adapt "The Office" for American audiences, they auditioned in several comic character actors, including Seth Rogen, Bob Odenkirk, Kathryn Hahn, and Adam Scott. Though those actors didn't land the parts, they did end up with major roles in other critically-acclaimed movies and TV shows, including "Knocked Up," "Abigail All Along," "Better Call Saul," and "Severance."

Lorne Michaels jokingly offered the Beatles $3K to reunite on 'Saturday Night Live,' which John Lennon and Paul McCartney briefly considered.

The best celebrity cameos on 'The Simpsons'

As the show became a pop culture sensation in the late '80s, it began attracting celebrities eager to get in on the fun. This list ranks some of the best of those appearances, including Meryl Streep, Paul McCartney, and Dustin Hoffman.

The 1977 'SNL' Mardi Gras special is considered the show's biggest disaster

An on-location episode of the then-young sketch show featured drunken heckling from the audience, technical difficulties amid the broadcast, and beads being pelted at cast members.

'Truth or Consequences' was the first TV quiz show

The game—which forced contestants who answered questions incorrectly to face "consequences" in the form of wacky stunts—debuted in 1941 with a one-off experimental broadcast on WNBT, then reappeared on NBC in 1950. In 1956, a fresh-faced Bob Barker made his television debut as the show's new host.

'Ted Lasso' didn't generate more American interest in soccer, but it might've made the game more comprehensible for them.

HBO premiered the modern stand-up special in 1975

When they appeared on TV, stand-ups were typically limited to five-minute spots on late-night talk shows, like "The Tonight Show." That changed with the fledgling HBO, which offered comics hourlong slots. The first was "An Evening with Robert Klein," a special that would define "the hour" for decades.

Before 'SNL,' producer Lorne Michaels was a performer

Michaels was a costar on "The Hart and Lorne Terrific Hour," a popular show on the Canadian network CBC. As these clips show, it was a standard variety show, something Michaels would intentionally react against with "SNL."

Watch every 'Simpsons' short from 'The Tracey Ullman Show'

Before it was a standalone sitcom, "The Simpsons" began in 1987 as a series of interstitials on "The Tracey Ullman Show," a short-lived sketch comedy show. You'll notice some slight differences—off-kilter voices, oddly drawn characters—but the series' premise was there, leading Fox to spin it off into its own show in 1989.

Jim Henson's lone Oscar nomination was for an experimental short film he made in the '60s that features no puppets.

Mario's archnemesis hosted a children's show in the 1980s

"Super Mario Bros." grew so popular in the '80s, even King Koopa, the video game's villain, had his own television show, though it's been all but erased from TV history. There's good reason for that: It was a bizarre enterprise, featuring '30s cartoons, a grumpy stand-up comedian, and cheap production.

'The Wizard of Oz' flopped in theaters but exploded on TV

The film cost $2.7M to make—$1M more than the average production in 1939, but didn’t recoup it for almost two decades. Its success is mainly due to television. It aired annually from 1956 to 1965 and was watched by more than 49% of all television viewers.

'Jeopardy!' was conceived as a way to earn back skeptical audiences' trust

In the wake of the ‘50s scandals, networks were reluctant to greenlight new quiz shows. Merv Griffin’s wife suggested he flip the formula on its head, providing contestants with the answers (the exact act that had led to the scandals) and asking them to provide the questions. “Jeopardy!” premiered in 1964, effectively reviving the genre. It eventually became the top-rated quiz show in history with 23 million viewers.

A comprehensive history of 'The Simpsons'

This documentary explores the wild trajectory of the show, from Matt Groening's early underground cartoons to its status as a groundbreaking pop culture phenomenon.

Cookie Monster evolved from the Wheel Stealer, a monster obsessed with a wheel-shaped cheese snack.

The first cast members were relatively unknown 'enlightened amateurs'

“SNL” producers aimed to cast relative newcomers for the show’s first season, convinced that amateurs would infuse the show with the countercultural spirit Lorne Michaels envisioned.

'Follow your enthusiasm. It's something I've always believed in. Find those parts of your life you enjoy the most. Do what you enjoy doing.'

- "Muppets" creator Jim Henson (1936-1990)

How HBO pioneered the hourlong stand-up comedy special

Stand-up comedy was already on television in the 1970s thanks to Johnny Carson, but comics were limited to clean sets that typically lasted five minutes. HBO, on the other hand, offered stand-ups the opportunity to air their unadulterated material like they would at a club.

'The Larry Sanders Show' redefined the American sitcom by removing audience laughter, a move that seemed counterintuitive for a television comedy.

Watch the 'Star Wars Holiday Special,' a 1978 spin-off that became a cult classic

The CBS television special is a hokey variety show that was widely panned after it aired and, as a result, was never officially released on home video. George Lucas had little involvement, though it did feature the original cast alongside guest stars like Bea Arthur. Interestingly, it also features Boba Fett's first appearance.

'Lazy Sunday' was YouTube's first viral hit

Initially aired on television, the 2005 "Saturday Night Live" digital short featuring Andy Samberg and Chris Parnell took off on YouTube, becoming one of the platform's first viral videos. The song may be a joke, but its success underscored how online video could extend the lifespan of regularly televised content.

Before it became the home of 24-hour prestige TV, HBO used to sign off each night.

Before it was a popular book, 'A Hitchhiker's Guide to the Galaxy' began as a radio series

The science-fiction comedy began as a radio play on BBC Radio 4, broadcast between 1978 and 1980. The first novel appeared in 1979; two years later, it was adapted for television.

Big Bird was almost included on the Challenger mission

As part of NASA's early outreach ideas tied to the Teacher in Space program, Sesame Street's Big Bird was briefly considered for a Challenger flight, but the plan was dropped because the oversized costume could not fit safely inside the shuttle.

Mel Brooks got his first big break in 1950 as a writer on Sid Caesar's 'Your Show of Shows,' a pioneering TV variety show.

A low-budget, Seattle-based comedy show launched Bill Nye's on-camera career

"Almost Live!" began in 1984 as a Sunday evening talk show before evolving into a sketch comedy show that served as the lead-in for "Saturday Night Live" on NBC's Seattle affiliate station. Besides Nye, TV stars Joel McHale and Lauren Weedman were regular cast members.

2 'Simpsons' producers break down the show's turning points

Longtime director David Silverman and showrunner Matt Selman walk you through some of the show's biggest turning points, from the early days on "The Tracey Ullman Show" through its biggest guest stars and eerily accurate predictions.