“No honey, open wider–like this.”
Klezmar music!
I know because I was getting laid when the radio station we had on changed from rock and roll to a new show with…klezmar music!. We were both laughing to hard to continue.
“Eraserhead” could lead to nookie in my vicinity. Great art makes me feel sexy.
Anything by R. Crumb.
A similar thing happened to me, but with digeridoo music (Xavier Rudd.) One of the reasons why you should make a specific playlist if you’re going to get it on to music.
What, this doesn’t do it for you and yours?
Richard McBeef.
“Mr. Brownstone” might but it won’t be the kind you’d like.
So, um…how…
…I can’t say it. 
Vogon poetry.
Various of the songs mentioned in Dave Barry’s Book of Bad Songs, especially in the chapter Songs Women Hate. When He Hits Me It Feels Like a Kiss especially comes to mind.
A video of a C-section.
The preserved, stuffed and heroically posed corpse of your mother, with an altar in front of it.
The World According to Garp.
Anything involving Lorena Bobbit.
Polka.
Fingerpainting… or at least it better not!
I was gonna go with Annie’s first one, plus:
Cornflake Girl.
Diane by 3 Pound Thrill.
Fish Heads.
Anything by They Might Be Giants.
I used to Love Her, But I Had To Kill Her, or whatever that song’s called.
Rape Me by Nirvana.
ETA: TMBG might get you the positive attentions of a nerd, but if a TMBG song comes on mid-makeout, depending on the feelings about the band it would probably either lead to a buzzkill, or stopping what you are doing to sing along with the song.
I might interrupt sex with inappropriate laughter if during the boink I heard Jim Morrison singing “This is the end…”.
Reading from the 1830 novel Paul Clifford, by Edward George Bulwer-Lytton. It begins, “It was a dark and stormy night…”.
On the wall – Saturn Eating His Son, by Francisco Goya (you might know this one alternately as “Cronos Eating His Children”).
And playing at a low volume for background ambience, Lou Reed’s Metal Machine Music.
Good times… 
37 posts and no Salo?
That’s the thing with almost all the answers in this thread: most of them will get SOMEONE laid. I’m sure there are quite a few people out there who could get laid with Salo, although the couple times I’ve seen it in a theater it’s been all about the walkouts. And it’s one of the DVDs that I’m almost sure to get back quickly when I lend it out.
Still, it’s de Sade, who has a lot of followers, n’est-ce pas?
The reason I nominated The Pizzle of the Chrizzle is because it’s got gore AND Jesus. Both pretty non-boneriffic. Still, I’m sure that right now there is someone out there somewhere frame-by-framing the oohIcanseehisribcage scene. (Reminds me; must move it into the Horror section when I get to work.)
The movie Killer Condom