Once I was watching Downhill Racer on TV with my college roomies, and when Robert Redford started to get it on with the Exotic Love Interest, I began singing Rodgers and Hammerstein’s Climb Every Mountain.
This is a little bit different, but…at the end of The Manchurian Candidate remake that I saw last summer, a man yelled out, “George W. Bush has a chip in his brain, and Cheney and Halliburton put it there! Vote that piece of shit out of office!”
We live in interesting times, indeed.
Harry Potter and the Chamber of Secrets, opening weekend, Los Angeles college town. Everyone who’d read the book knew it was coming, but at the end of the film when Dobby the house elf declares “You will not touch Harry Potter!” and blasts Lucius Malfoy across the hall, it was such an unexpectedly badass moment that the audience was briefly speechless. Then some guy in the back called out, “Do-BBY” in that type of, um, ghetto “giving props” voice. (If there’s a better term for it, I do not know…) That broke the silence and we all laughed and applauded. 
A friend of mine heard this…
I don’t recall the name of the movie, but there was a very quiet scene, broken by the sound of a zipper being unzipped.
Some girl in the audience says "You know I heard that befo’ " just loud enough to be heard by the entire audience, which erupted in laughter.
I wish I’d been there.
In Spiderman 2 when Harry Osborne found out that Peter had killed his dad, he says “you killed my father” I obviously followed up with “prepare to die.” It got a chuckle out of the girl I went with, I was pretty happy with myself.
I went to see Matrix: Reloaded opening night. Yes, it was a mistake. One of the previews was for Terminator 3: Rise of the Machines. Partway through the trailer, an audience member shouted “where’s Linda Hamilton”. I replied with a louder shout “Linda Hamilton’s a slut”. Did not make much sense, and still does not, but it got me many laughs from fellow theater goers.
Sounds kind of like what my brother blurted out when we were kids.
We were watching some PG-rated comedy movie with our mom, and in one scene the heroine, obviously stressed out, makes a complaint something like: “I’m being chased by Russian spies, I just found a bomb in my car, I’ve just gotten fired from my job because somebody planted LSD on me, and to top it all off … I’m having my period.”
Whereupon my younger brother turned to my mom and, in a voice loud enough for all to hear, asked, “MOM, WHAT’S A PERIOD?”
(Note: My mom told him, and then later, when a woman in the movie was found stabbed to death in her bed with blood everywhere, my brother commented, “WOW, SHE MUST’VE HAD A BIG PERIOD!”)
My wife and I went to a restaurant and a movie with another couple of friends…and my friend and I always try to embarrass and humiliate each other in public with an ackward joke or insult especially with the wives there. Well my buddy got me in the restaurant in front of the waitress and a couple of nearby patrons by commenting about my pink thong was showing when I was bending down to pick up a napkin…me…a guy pushing 300 lbs. Ha ha buddy…laugh it up…you’ll get yours!
While we were waiting for the movie to start (I think it was Forrest Gump), there’s that dead silence between the end of the trailers and the start of the movie and the movie crowd fell very silent as soon as the trailers ended (but the lights were still on)…a perfect time to spring my big question…“So Glenn, has your penile implant taken root yet?” Laughter from 3 rows in front and 3 rows behind erupted as my buddy slinked down in his chair (with a pained smile on his face) as the lights went down and the movie started. Ah, sweet revenge.
[hijack]Papa Zappa once asked me if I’d have sex with Robert Redford for a million dollars.
Without missing a beat, I said “I can’t afford that much!” (heh, maybe this should have gone in that thread about best comeback lines :D) [/hijack]
I don’t have any funny lines, but Papa Zappa has a couple of good stories:
While sitting through some dreadful Beatles movie, with lots of happy music, one of the characters is dancing across a bridge. Grandma Zappa shouted “Jump, [homophobic slur]!”. I believe penis ensued
During a screening of the 1973 version of Lost Horizon (calling it mediocre would be charitable), a young boy was chattering loudly throughout, annoying all the other viewers. However, after the avalanche scene, he asked loudly “Mommy, are they dead?”. The audience totally broke up.
And there was the time he attended a movie that involved a character’s eyes getting gouged out. With a friend who had seen the movie before. At the crucial scene, the friend started playing a recording of “I Can See Clearly Now (The Rain Is Gone)”. They were invited to depart the theatre
Always a nice thing to have happen.
That happened in my theater on opening night. Several friends of mine from various parts of the country tell me that it happened to them, too.
Our oldies theater was showing War of the Worlds.
Near the finale, a Martian ship crashes.
A hatch opens, and a dying alien is seen.
It twitches a bit, then falls still.
There is a dramatic pause.
One of the movie characters shouts, “It’s dead!”
From the back row, a very good McCoy impression shouts, “Jim!”