The Orgasmatron Booth
Maybe I should be more surprised that Woody Allen would come up with one of the most well known pieces of SF sextech in Sleeper, his one and only SF movie to date, but all I can think is that anything that demonstrates how easily people can be replaced by machinery is right up his 1970s comedy neuroses alley. Sure, science may have tried to create the real thing, but the fact remains: Is there a closet that I can walk into and experience multiple climaxes without the presence of another human being and risking repetitive strain injury? No. And that's the true tragedy here.

The Excessive Machine
Unlike the Orgasmatron, Barbarella's Excessive Machine is made for evil purposes, apparently (Unless you think that "Executioner" is some kind of porny euphemism), but you can't deny that with a little reworking, this organ-based organ-replacement could bring happiness to a great many people everywhere, while being more aesthetically-pleasing to look at than any of the inventions seen so far on popular internet destination Fucking Machines (Dear everyone: That link is very NSFW. Do not blame me when you click on it in your place of employment and get in trouble. The clue as to why may be in the name of the site).

Sex Rays Of Various Types
Whether it's Flesh Gordon's Sex Ray or Orgazmo's Orgazmorator, there's no denying that there's something primal about the idea of making that penis/gun substitution a little more literal than usual. The best variation of this idea belongs to 2000AD's satirical Big Dave strip from the 1990s, wherein Saddam Hussein unveiled his plan to defeat the West once and for all by using his Love Gun - built by aliens, of course - to turn opposing armies gay, and therefore - proving the reasoning behind the US military's ban on homosexuals - useless as soldiers.

Freaky Virtual Reality Sex
http://io9.com/5054503/the-dos-and-donts-of-cybersex
Lawnmower Man's face-melty sex scene may look somewhat cheesy now - and make you go "Hey, it's Frank off Lost! But young!" - but let's face it; Second Life really doesn't compare to the virtual reality insect fetish sex that this movie promised us. Science fiction loves to suggest that VR will open up all new worlds of sexual exploration (Even Star Trek: Deep Space Nine had Quark's holodeck suites, which you knew were dens of perversity and characters fantasizing about Dax and Kira getting it on with them), but the reality has proven to be somewhat lacking.

Sexbots In General
I know, I know. Sexbots; they're the android dream for all of us, whether they're Cherry 2000, Battlestar Galactica's Six or any of a large number of other possibilities, there's something amazingly alluring to many people about the idea of a lifelike play partner that only does what you tell it to do (or maybe not). But when I don't care how realistic they think robots are getting, that whole dead-eyed look just doesn't do it for me just yet. Give me a call when they've reached Tricia Helfer level - or maybe Sky-Doll.

I'm Not Feeling Myself Tonight (1975). One of those bizarre Britsploitation films that could only have come from the groovy 70s. Barry Andrews is a virgin who goes to work in a weird sex research institute, where patients run around naked and everybody does nude aerobics. But Andrews still can't seduce the hot secretary — until he invents a machine (nicknamed Agnes for some reason) which puts out a "sonic aphrodisiac" which turns anyone into a sex maniac. Andrews doesn't quite manage to seduce Cheryl the secretary, but does have fun using Agnes on his overbearing boss, and a pesky woman who's campaigning for moral decency.

Randy The Electric Lady (1978). Desiree Cousteau plays Randy, who's having a hard time reaching climax — until she goes to a weird sex clinic, where she manages to climax so hard, she explodes all their computers and measuring instruments. Then the researchers realize that Randy secretes a special substance called Orgasmine when she climaxes, and everybody who's exposed to Orgasmine turns into an easily controlled sex rabbit. Of course, being a mad sex doctor, the head researcher Dr. Harrison wants to use Orgasmine to RULE THE WORLD! Bwa ha ha ha....

The Ultimate Attraction (1998). The source of the clip featured above. Written by scifi pornmaster Rolfe Kanefsky, Ultimate is loosely (and I stress "loosely") based on the classic comic Click by Milo Manara. But whereas in Manara's comic, a woman has a brain implant that cranks up her sex drive at the twist of a dial, Kanefsky's version is a directional beam that affects anyone you point it at. And somehow, in the course of Ultimate's storyline about a troubled mom-and-pop gym that finds a sex-ray, the device gets changed so that any electrical device can turn into a horniness inducer. Like the boombox in this clip, where a bodybuilder's walkman runs out of batteries:

Flesh Gordon (1974). The Emperor Wang is using a "sex ray" to turn everyone on Earth into uncontrollable sex maniacs. So it's up to Flesh and his friends to stop him. At least it's better than the awful sequel, in which a supervillain tries to use an "impotence ray" to rob Earth of all its virility. Ugh.

Flash Gordon (1980). Weirdly enough, both Gordon films feature the villain using technology to make people into sex-fiends. In Flash, Ming uses his weird power ring to hypnotize Dale Arden into performing a sexy dance for him.

Shivers (1975). David Cronenberg's third film includes much of the "body horror" for which he became famous. A parasite which scientists developed to replace damaged or diseased organs goes out of control and starts turning men and women into sexual predators. The host can only spread by having its victims sexually overwhelm other people, and a new self-contained tower building becomes a perfect breeding ground. There are lots of bloody scenes of mangled faces, and then it ends up with the world's most disturbing pool party:

Torchwood, "Day One" Trust crazy Doctor Who spinoff Torchwood to go way, way over the top when it comes to alien sex-parasites. A purpley gas takes over Carys, a lovelorn woman, and turns her into a hot sexpot who goes around seducing men... and then reducing them to a little powder when they orgasm. She seems to have the power to sex-craze other people too, since she's able to get the straight (as far as we know) Gwen into a hot snog-a-thon. Here's her best moment:

The Curious Dr. Humpp (1966). We've already sung the praises of this bizarre hybrid movie. Dr. Hummp needs to absorb the erotic energy from rabbiting nymphomaniacs to keep himself and his pet brain healthy, so he kidnaps nubile young people and keeps dosing them with powerful aphrodisiacs to keep them in the mood.

Barbarella (1968). The original scifi porn film. Jane Fonda's blonde mega-mane and anime eyes radiate sexuality. It starts with a zero-G spacesuit strip show in Fonda's shag-carpeted space capsule, and then she fights off angry dolls in her ripped stockings. Plus she hooks up with a hunky space angel.
Money shot: Duran Duran puts Barbarella into his sexomatic Excessive Machine, only to have her burn it out with her over-the-top tantric energy.

Flesh Gordon (1974). A crazy pastiche of the 1930s Flash Gordon serials, featuring Flesh and his sidekick Dale Ardor. The Emperor Wang bombards the Earth with a sex ray from planet Porno and it turns everybody into a sex fiend. This is somehow a problem. Lesbian queens in black swan spaceships, bearded men with pasties, penisaurs, bearded men with drag queen makeup, sex robots... The whole thing is intensely campy, even by 70s porn standards, and feels like Rocky Horror with more nudity and less singing. And yet it features special effects by people who went on to work on the Star Trek and Star Wars movies.
Money shot: A giant claymation monster, voiced by Craig T. Nelson from Coach, grabs Dale and carries her up a wall like King Kong. Flash has to battle the lumpy creature to save his hot sidekick. Here's the trailer:

Latex and Shock (1995). Probably Michael Ninn's most famous porn films, Latex and its sequel try for a "cyberpunk" aesthetic without actually comprehending cyberpunk. But that's okay, because the actual plot about a psychotic telepath imprisoned in a future dystopia is weird enough on its own. Malcolm Stevens has the ability to read people's thoughts, and uses it to discover their sexual fantasies. (Instead of getting rich, or escaping from his asylum.)
Money shot: In the second film, a female therapist tries to use shock treatment to cure Stevens, but her assistant gets drawn into a telepathic nightmare where she's trapped with two sexy gargoyles.

Cyberella: Forbidden Passions (1996). It's just your standard-issue cyberpunk redemption-through-sex afterlife story. Mara is a famous virtual reality designer, until she dies in a fire while plugged in to VR. Instead of going to the afterlife, her soul gets trapped in cyberspace, where she meets God. And God tells her to go into other people's VR worlds and have sex with them, until she transcends this plane of existence. Yes, it's that great.
Money shot: Cyberella enters someone's cracked copy of Mac Paint and they have paint-splashing VR sex.

Orgazmo (1998). A naive Mormon missionary gets drawn into doing porn and portrays a superhero named Orgazmo, who wields a ray that causes people to climax in this film by Trey (South Park) Stone. And then, when Joe Young decides to fight back against the sleazy film producer who exploited him, he suddenly finds that he can wield the power of Orgazmo for real.
Money shot: Orgazmo flying-kicks real porn star Ron Jeremy, who explodes into little pieces... only to come back a few minutes later.

Rod Steele 0014 and The Ultimate Attraction (2000-2002). Horror auteur Rolfe Kanefsky has a sideline in scifi soft-core porn movies, which often air late at night on premium cable and then come out on "unrated" DVDs. (He also wrote the totally bizarre Emanuelle vs. Dracula.) Both of these films involve a "clicker" that can increase the horniness level of anyone you point it at, ripped off from Manara's Click. In Steele, a James Bond parody loses track of his arousal-causing gadget and it creates mayhem. In Attraction, a mom-and-pop gym's staff uses the device to save the gym from a gym mogul who wants to buy them out. Really.
Money shot: In Attraction, it turns out the clicker doesn't just increase your arousal, it can transform your body as well. Here, a dorky guy uses the clicker to turn his gym coworker into a supermodel: