So there you are with your popcorn and your enthusiasm, waiting for lightning to strike, but instead of being blown away by $200 million worth of spectacle you get Transformers: Age Of Extinction.

Nobody goes to the multiplex for Great Art, but if you can’t get two hours of decent popcorn, what’s the point? You’re better off staying at home, watching the kind of films your local plex would pay not to show.

We’re not just talking about amateurish acting, dime-store effects and absurdly quotable dialogue, but also concepts so thoroughly bizarre you can’t believe anyone was willing to throw money at them. Ray Milland’s head being grafted onto Rosey Grier’s body? Only in the 1970s!

No matter how weird the going gets, though, these pictures never lose sight of why we go to the movies – we are there to have fun, not watch ice melt for two hours while feeling disappointed. It’s a lesson the makers of sequels, reboots and superhero movies would do well to learn.

20. From Hell It Came (1957)

A picture guaranteed to bring out the worst puns imaginable (“His bark’s worse than his bite”, “what a sap”, “surely knot” etc.), From Hell It Came convincingly depicts the “old legend” of Tabanga, the tree monster who, as any anthropologist will tell you “walked to avenge its wrongs.”

On a “savage island” in the South Seas populated by white English-speaking extras, a Prince named Kimo is sentenced to death by ceremonial dagger for supposedly murdering a chief, but every b-movie fan knows that when a wrongly-convicted man swears vengeance on his persecutors before being buried in a hollow tree trunk, it’s only a matter of time before he returns as another actor in a silly costume.

And what a costume it is. Unlikely to scare anyone except the film’s financial backers, who likely imagined the shirts disappearing off their backs, Tabanga was designed by an uncredited Paul Blaisdell which isn’t too hard to guess as the ambulatory antagonist possesses the same fluid grace as his finest creation, the conical cucumber creature from Roger Corman’s It Conquered The World.

19. Grizzly II: The Concert (1987)

All concert and no grizzly, this belated sequel to William Girdler’s 1976 killer bear opus was still shooting when financial squabbles caused the Hungarian government to shut the production down, leaving the unfinished picture in limbo until a leaked workprint appeared online in 2007.

Wish we could say this is The Greatest Movie You Never Saw, but Grizzly II is to Girdler what Jaws II was to Spielberg, only much, much less. It does however feature Oscar winner Louise Fletcher as a park superintendent who wants that evening’s Nazareth concert to go ahead despite the mauling of fellow Oscar winner George Clooney, who made the mistake of wandering past a sign reading CLOSED BECAUSE OF BEAR DANGER with pals Charlie Sheen and Laura Dern.

Then there’s John Rhys Davies in the Robert Shaw role as a “French-Indian” bear-trapper who claims that in order to catch a grizzly you have to act like a grizzly, think like a grizzly, smell with his nose and wander through the woods in daylight while the rest of the movie is taking place after dark.

Throw in Charles Cyphers (Halloween) as another grizzled grizzly hunter, Deborah Raffin (Death Wish 3) as head of “Bear Management” and Deborah Foreman (April Fool’s Day) as lead Teen In Peril and you have a ‘movie’ that’s irresistible to fans of watching famous faces demean themselves for a paycheck.

18. Santa Claus Conquers The Martians (1964)

Shot in a converted aircraft hangar by an inexperienced crew, with thrift store costumes and props made from household items, Santa Claus Conquers The Martians is a perfect example of what happens when an enterprising producer attempts to make a children’s Christmas movie, but can only afford to mount it on a budget of half a shoestring.

The Martians here are not the malevolent creatures depicted in War Of The Worlds but unemployed stage actors wearing green costumes, green face paint and, for some reason, TV antennae, which prompts one Earth girl to enquire, “Are you a television set?”

Ironically, the Martian children have intercepted Earth television signals and, exposed to broadcasts from the North Pole, become despondent at the prospect of never meeting a well-fed alcoholic in a red suit. Considering what the lack of a proper childhood did to Michael Jackson, it’s understandable that the parents decide to kidnap Santa and bring him to Mars, but the mission is endangered by Voldar, who we know must be the epitome of evil because he has a moustache.

Called “the worst science fiction flick ever made” by The Monster Times, the movie marked the screen debut of Pia Zadora, who is here surrounded by cardboard robots, a guy in a polar bear costume and aliens armed with Wham-O Air Blasters. The future ‘star’ has precious little screen time and says next to nothing, but boy did she start as she meant to go on.

17. Rat Man (1988)

Any hope that this was going to be a superhero parody in the vein of Ray Dennis Steckler’s awesome Rat Pfink A Boo Boo was quelled by the tagline: “He’s the critter from the shi**er!”

In the main story, swimsuit model Eva Grimaldi is taunting her photographer (“The only thing he’s got that clicks with me is a shutter”) when an attack by the eponymous creature, who does indeed emerge from a latrine, forces them to seek help at a nearby doctor’s residence.

Unfortunately, the doc seems to know more about ol’ ratface than Ms Grimaldi is comfortable with, ultimately ranting about how his “Greatest achievement” was to fertilize a monkey ovum with the sperm of a rat, which he thought would win him the Nobel Prize but instead created a monster (what’re the odds?).

Intercut with this is the arbitrary sub-plot of sister Janet Agren (City Of The Living Dead) and writer David Warbeck (The Beyond) searching for Grimaldi by puttering about in dark, deserted houses and storming ideas for Warbeck’s new novel. Since they never do very much or share screen time with the other performers, their scenes feel like an afterthought tacked on in post-production, as does the abrupt, unbelievable ending.

16. Massacre In Dinosaur Valley (1985)

Directed by the auteur behind Women In Fury, Undergraduate Girls and the disarmingly titled A Policewoman On The Porno Squad, Massacre In Dinosaur Valley is loaded with gratuitous nudity, cheesy laughs, gratuitous nudity, fake gore and did we mention gratuitous nudity?

It’s your typical story of an Indiana Jones-ish adventurer and two lingerie models who, following a plane crash, are set upon by a succession of leering voyeurs. First, and most bizarre, are the tribesmen who force the girls into their birthday suits so they can dance for a claw-handed deity who emerges from a cloud of smoke.

Escaping with suspicious ease, they next encounter a perverted slave owner. While he attends to his illegal mining operation, the girls are “entertained” by his lesbian henchwoman, who whisks them off for a first date they’ll never forget.

The film also lends itself to a drinking game: take a drink every time the director comes up with another way of denuding his cast.

15. Dracula The Dirty Old Man (1969)

Had history played out differently, Dracula The Dirty Old Man would’ve been just another forgettable no-budget monster nudie flick. To the gratitude of bad movie fans, however, the director lost the soundtrack in post-production and decided to redub it as a comedy, turning a threadbare sex farce into a movie that must be seen to be believed.

For budgetary reasons, Count Dracula lives in one of California’s Bronson Caves and, after transforming a nosy journalist into a lycanthrope named Irving Jackalman, instructs him to procure young virgins. When the starlets are delivered to his cave, the Count ties them up, starts fondling them and….that’s when the movie goes mad.

Dubbed with the voice of a bad Bela Lugosi impersonator, the Count points out technical goofs and jokes about how cheap the movie looks. In between denuding starlets, he’ll look around his cave and say, “I’ve got to get a new interior decorator.” At one point, he says, “I am Count Dracula. Which is Alucard backwards. So you can call me Ali.”