Star Trek: Phase II, 1977  Star Trek creator Gene Roddenberry began plans in 1977 for a follow-up to the original series that had run from 1966-69, to launch what at the time was planned to be be a fourth US TV network, Paramount Television Service. But Paramount CEO Barry Diller eventually decided the script would work better as a feature film, and, perhaps more importantly, the plans for launching the channel fell through altogether. A version of that script would become Star Trek: The Motion Picture, which hit cinemas in 1979; in 1987, the space saga made its long-awaited return to TV with Star Trek: The Next Generation; and in 1995, Paramount finally did launch its own network, UPN, with the series Star Trek: Voyager.  This 1982 animated series, co-produced by Japanese and French companies, would have followed a descendant of Lupin III – the thief who uses his skills for good in Monkey Punch’s popular manga series. After Lupin III made his first appearance on Japanese TV in 1967, he spawned a media empire, including several manga, TV series, movies and video games. But this next-generation version, which was calculated in part, some fan sites thought, to serve as the series’ crossover to Western audiences, was not meant to be – some online speculation has it that Leblanc’s estate’s asking price for use of the character was too high.  Cheers creators James Burrows and Glen and Les Charles asked Joe Keenan, the author of Blue Heaven, to create a sitcom for their production company in 1991. He came up with this pilot, which followed a Gloria Swanson-esque actress in the 1930s, played by JoBeth Williams. At the time, Keenan called it “gay-sensible without being so gay we couldn’t get sponsors.” (Example: Gloria asks her longtime directing partner what would have become of him if he hadn’t worked with her. He answers, “Heterosexual, probably.”) Alas, test audiences eviscerated the forward-thinking pilot, and Keenan went on to write for the more mainstream hit Frasier.  Sick in the Head, 1999  Before Judd Apatow invented his guy-centric subgenre of romantic comedy films, with movies like The 40-Year-Old Virgin and Knocked Up, he was a legend in television – mainly for his ability to create shows so cool they ultimately failed. His cult favourites Freaks and Geeks and Undeclared made it to air, but failed to attract large enough audiences. Sick in the Head was among three other shows he created in the ‘90s that didn’t get past the pilot stage, and it has become the stuff of wistful, what-could-have-been legend among US TV nerds. Apatow shot the pilot for US network Fox in 1999, casting the affable David Krumholtz as a young, clueless psychiatrist and a then-unknown Amy Poehler as a patient who’s on her 13th therapist. But a change at the top at Fox meant a change in fortune for Sick in the Head, which didn’t make the schedule.  Heat Vision and Jack, 1999  This sitcom, co-created by Community mastermind Dan Harmon, parodied ‘80s action shows like Knight Rider and starred Jack Black as a former astronaut who gains super-intelligence from the sun’s rays, and Owen Wilson as the voice of his talking motorcycle. Ben Stiller directed the pilot, but Fox rejected it. Like Sick in the Head, this show, too, was considered for the 1999 season, which means that in an alternate universe, Fox could have revolutionised network TV in the US that season. Instead they went for a half-hour repackaging of Ally McBeal, called Ally, and Malcolm in the Middle – a solid but safe show that introduced the world to Bryan Cranston before Breaking Bad. Heat Vision and Jack lives on in internet clips, as well as a possible animated adaptation, which was still rumoured to be in the works as of 2014.  Star Trek’s spiritual cousin, Star Wars, had its own adventures in failed TV pilots. Creator George Lucas announced in 2005 that he was working on a show set in the time between the franchise’s Episode III: Revenge of the Sith and Episode IV: A New Hope. At the time, Lucas gave Total Film magazine an intriguing description of the series: “It's funny and there's action, but it's [a] lot more talky. It's more of what I would call a soap opera with a bunch of personal dramas in it.” Though many scripts were written, visual concepts were created, and Battlestar Galactica creator Ronald D Moore spent time developing the show, which was referred to within production company Lucasfilm as Star Wars: Underworld, Lucas ended up scrapping the plans due to budget concerns.  In 2012, The Squid and the Whale director Noah Baumbach was on track to adapt Jonathan Franzen’s novel for HBO – it seemed like the very definition of a surefire hit. The show lined up an impressive cast including Maggie Gyllenhaal, Ewan McGregor, Dianne Wiest, Chris Cooper and Greta Gerwig. But the network ultimately passed on the project, and last year Baumbach told public radio station WNYC that the book was too complicated for a serialised TV treatment and speculated that the budget was too high for a mere family drama.  In 2011, Canada’s Space Network commissioned a pilot for a show that tells the story of a recently defrosted arctic 30 years in the future. The plot revolved around a small town beset with researchers, entrepreneurs, and government agents desperate for what may be one of the few remaining oil resources in the world. There’s also a murder mystery, a gun-toting conservationist, and a cage match. Alas, the network decided that corporate science, international border disputes, and global warming weren’t what they wanted in a series, so they ran Borealis as a two-hour movie in 2013 and left it at that.  The Chinese web drama, which aired earlier this year, was based on Jidan’s novel Are You Addicted? and followed the lives of gay high schoolers with fraught family lives. But after four weeks on Chinese video streaming service iQiyi, government censors pulled it, upsetting many of its millions of viewers. Though no official reason was given, its fans lamented the government’s presumed anti-gay bias online: “When will our society become a multicultural and more tolerant one?” said one, quoted in the South China Morning Post. The first season is now available on YouTube as Addicted. A second season is unlikely ever to go into production.  John Hodgman made his name writing humour books and serving as a correspondent for The Daily Show – in the US he was the personification of the PC in Apple’s famous Get a Mac campaign. After appearing on FX’s series Married, he wrote this pilot at the network’s request, based on his experiences growing up in a boarding house in Massachusetts as a precocious only child. The real clincher: he would, as an adult in his 40s, play himself at 14 – because his character saw himself as a grown man who was above all the teenage nonsense going on around him. FX and another cable network ultimately turned it down. (Hodgman says it was too “sweet” for the “edgy” sensibilities in cable now.) Just hearing Hodgman talk about the show’s concept is funny enough; lucky for us, the new podcast Dead Pilots Society also recently staged a read-through of the script.  If you would like to comment on this story or anything else you have seen on BBC Culture, head over to our Facebook page or message us on Twitter.  And if you liked this story, sign up for the weekly bbc.com features newsletter, called “If You Only Read 6 Things This Week”. 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From a Star Wars series that never happened to a censored Chinese drama, Jennifer Keishin Armstrong looks at some intriguing programmes that never made it to our screens.