Well, it doesn’t seem to be available on DVD in the US, although an American remake (called Quarantine) is in the works. I saw REC on www.veoh.com. Had to register, but it’s free.
Looking at that list of scary scenes reminded me of the scene at the end of Carrie
where the arm comes out of the ground and grabs the girl laying flowers on the house site/grave.
I was watching it at home on tv. I didn’t sleep that well that night.
If my colon had been full at the time, I probably would have squirted while watching the scene in The Exorcist when Reagan walks upside down and backwards up the stairs.
Not only did I jump when that happened, but the guy in front me at the theater immediately spun around, wide-eyed, and shouted “FUCKDIDYOUSEETHAT?!?!”
Scared me more than the Sloth guy in the movie.
The other soiled shorts moment in The Dark Knight was when the fake Batman slammed up against Dent’s window. Was not expecting that in the slightest.
The Changeling, when you see the boy’s ghost under the floor of the little girl’s bedroom, and when the ball comes bouncing down the stairs.
An oldie and not so goodie, in Curse of the Demon there’s a long, distant shot of a critter moving very quickly down an avenue of trees toward this poor slob standing by his garage. The effects are primitive, but it worked for me.
In Forbidden Planet, when you see the metal steps bending under the weight of the invisible monster.
In Them, when the little girl hears the sound of the ants and sits up real fast, and nobody notices. I’ve watched that movie recently, and it holds up well. I hope nobody remakes it.
The scene in Deathtrap when Christopher Reeve shows up at the door
The “hobbling” scene in Misery. Every foot in the theater left the floor.
Also, The Sixth Sense, when the little girl shows up in the boy’s tent…
I’m a wuss.
The Ring as well, but for me it was the moment when Samara walked up to the TV screen AND THEN STEPPED THROUGH IT. I completely recoiled into my seat in the cinema, much to the amusement of my boyfriend.
In The Dark Knight, when the mayor gets a shock at his window…
Trainspotting: “No I’ll clean those sheets!”
Oh, I see that’s not what you meant.
WarmNPrickly - your user name fits this thread perfectly. 
Warm yes, but prickly? You need more fiber.
Evil scary clown puppet in Poltergeist. Creepy-ass movie.
Oh man…
Me and my then girlfriend went to see Vacancy, a forgetable little thriller packed with MUSIC-GO-REAL-LOUD jump scares, faces suddenly at the window, shit like that. I thought it was pretty hokey, but my girlfriend was TERRIFIED. Now, I went out midway to use the bathroom, and coming back in, I was struck with an idea. See, the screen we were in had kind of a wall at the bottom, if you can imagine, just a low wall about three feet high between the front row and the screen itself. You walked past this row to get to the exit. And me and my girlfriend were sittng front row centre… see where I’m going with this?
So coming back from the bathroom, I crept onmy hands and knees under this wall, to where I knew my girfriend was sitting (I could see my nacho tray at the edge of the wall where I had left it). I waited and waited for the oppurtune moment, as in, when the music was reaching a creepy crescendo ( I could tell from the type of movie that the music would get loud, loud, louder, as if something would happen, then at its loudest… nothing; breathe sigh of relief, character turns round then BOOM! Face at the window/ in the mirror/ cat jumps out. Really, Vacancy is that predictable) So I waited on the music, and believe me, I couldnt have timed it better; I jumped up in the classic RAARRGH monster pose just as the music went BAM onscreen.
Now, here’s how scared of the movie my girlfriend was… when I left to go to the bathroom, she covered her eyes and wouldnt watch; and as such, she missed my monster scare!
Everyone else in the theatre, however, FILLED THEIR PANTS WITH POO. And then started laughing and jeering and throwing popcorn at me. I had to explain to my girlfriend why they were doing it. Good times.
I saw this movie when it originally came out in 1967. I was nine years old. And yes, I think I actually did soil myself when Alan Arkin took that leap.
That wouldn’t be Rear Window, would it? With Jimmy Stewart being confronted by Ramond Burr bent on murder?
For me, Carrie. The last scenes (“Carrie burns in hell”). I was towards the back of the theater and the whole place levitated – including me.
Another vote here for the end of Carrie. It gave me nightmares.
It was the killer in a mask that looked like the head of a pig, I think.
That scared the crap out of me too, along with the scene in The Grudge and its Japanese original, Ju-On, where the murdered ghost drags herself out into the hallway and down the stairs at the social worker.
Oh, and also the scene where the other woman is hiding under her blankets and the murdered ghost woman starts crawling up from the bottom of the bed, under the covers with her. They aren’t supposed to be able to get to you under the blanket – that’s the rule!
Oh, oh, crawling down stairs contorted crab-walk from the Exorcist. Ech.