4. Garth Marengi's Darkplace
Attempting to explain Garth Marenghi's Darkplace to someone who has never heard of it is a bit of a challenge, but even though it might sound nothing more than weird, it's absolutely worth giving a go. Airing in 2004, the show is a horror parody with the aesthetic of a lost eighties television programme, something that was purportedly never broadcast.
Across Garth Marenghi's brilliant six episodes is a hilarious parody of cheap, cliched horror and sci-fi programming, but to reduce the show to merely parody would be to do it a disservice. There's also a fantastic cast of characters played by the likes of Richard Ayoade and Matt Berry.
Parody may not be a new premise, but it's the utter uniqueness of Garth Marenghi's Darkplace that so entices viewers who watch its first and only season. That and the constantly high volume of laughs renders it utterly unforgettable.