Inception - The spinning hallway fight used a real spinning set
Let's ignore the fact that, despite what Christopher Nolan may think, spinning hallways are not the type of thing most of us dream about. If he'd made an honest depiction of our nocturnal experiences, it'd be a bizarre blend of David Lynch film, porn flick, and children's cartoon. What he did give us was some jaw-dropping special effects sequences—when Joseph Gordon-Levitt takes on a foe in a tilting corridor, we all spontaneously forgot what a whiny loser he was in 500 Days Of Summer.
And we all owe more respect now that we know the scene actually relied on practical effects, rather than CGI. Nolan's team built a revolving hallway and choreographed the fight around it. Hopefully the actors had puke buckets on set.
Cliffhanger - A stuntman zip-lined from one plane to another
Back when Stallone could still non-ironically star in an action film, Cliffhanger got our blood pumping early on with a mid-air heist that culminated in a character transferring from one plane to another via zip line. Even without the effects of today, this could have easily been pulled off with composite techniques.
Instead, they paid a stuntman $1,000,000 to do it for real. At 15,000 feet up in the air, Simon Crane, whose balls must one day be studied by science, delivered the goods, and hopefully never paid for another drink again in his life.
Skyfall - Yes, they were fighting on top of a real train
Director Sam Mendes instantly assured viewers that Skyfall would have nothing in common with the plastic bag bullshit of American Beauty by opening the movie with a fist fight atop a moving train. Any number of effects could have been put to use to make this look realistic, but the crew decided to take the YOLO approach to filmmaking by actually staging the fight on top of a real train. And anytime you actually see Bond's face? That wasn't any camera angle trickery. Daniel Craig's really up there, probably maintaining his cool by repeating his paycheck like a mantra throughout the whole thing.
Live Free Or Die Hard - They actually ramped a car into a helicopter
Though the Die Hard films will never be acclaimed for their realism, the fourth movie abandoned all semblance of seriousness with stunts that everybody thought could only come out of a computer. That car crashing mid-air into the helicopter might as well be from the latest Grand Theft Auto game.
But it was real. Some computers were used to enhance the images, but the shot itself involved an actual car flying into an actual helicopter. That fact, coupled with the film's title, may make this the most American moment in all of human history.