When Harry Met Sally (1989)
The Improvisation : Harry (Billy Crystal) and Sally (Meg Ryan) are dining at Katz's Delicatessen in Manhattan, where Sally proves it’s impossible for a guy to tell if a woman’s faking an orgasm... by faking an orgasm. A nearby patron orders her food: “I’ll have what she’s having.”
What Was In The Script: The entire scene was made up in order to give Sally a shining moment. The classic punchline was dreamt up by Crystal.
The Improvisation: “Why male models?” asks Derek Zoolander (Ben Stiller), moments after David Duchovny has explained exactly that.
What Was In The Script: Stiller actually forgot his line here, and merely repeated a question he’d already posited. Talk about getting into character…
The Dark Knight (2008)
The Improvisation: A small moment with a big bang. The Joker (Heath Ledger) blows up a hospital, but gets confused when only one tiny explosion happens. Jabbing at his detonator, delayed explosions go off, causing Joker to jump and then hurry off to his awaiting school bus.
What Was In The Script: This scene did happen in the script, but the explosions were delayed, confusing Ledger and prompting this nice little moment of in-character reacting.
The Godfather (1978)
The Improvisation: “Leave the gun,” says Peter Clemenza to Rocco, who’s just killed Paulie. “Take the cannoli.”
What Was In The Script: The first part of dialogue was present and correct, but the cannoli line was entirely improvised.
Dr Strangelove (1964)
The Improvisation: “Mein Fuhrer, I can walk!” Peter Sellers forgets that his wheelchair-bound nuclear weapons expert is in fact disabled, and cries this line jubilantly when he gets out of the chair.
What Was In The Script: The scene itself was scripted, but Sellers’ out-of-wheelchair moment wasn’t.
Saving Private Ryan (1998)
The Improvisation: Matt Damon impresses by coming up with his character’s entire backstory. He weaves a story for Tom Hanks about three brothers and a girl back home, filled with surprisingly vivid flashes of detail.
What Was In The Script: The encounter between the two characters was scripted, but Damon’s ad-libbing impressed Spielberg so much that he left it in the final cut.
Annie Hall (1977)
The Improvisation: “You never want to try anything new,” Annie (Diane Keaton) accuses Alby (Woody Allen) after they head to a friend’s house where cocaine’s on offer. Inspecting the white substance, Alby sneezes, sending powder everywhere…
What Was In The Script: The sneeze wasn’t scripted, and shooting had to be abandoned because the actors couldn’t stop giggling.
Reservoir Dogs (1992)
The Improvisation: “Was that as good for you as it was for me?” asks Mr Blonde (Michael Madsen), having just sliced off a cop’s ear in Tarantino’s central set-piece.
What Was In The Script: The ear-cutting scene was in the script, but Madsen was let off the leash to do whatever he wanted dialogue-wise.
The 40-Year-Old Virgin (2005)
The Improvisation: “You know how I know you’re gay?” Paul Rudd and Seth Rogen battle it out in a sublimely immature game that involves coming up with insults that, apparently, expose their latent homosexuality…
What Was In The Script: None of the lines rustled up by Rudd and Rogen were scripted.
Midnight Cowboy (1969)
The Improvisation: Dustin Hoffman and Jon Voight are walking down a busy city street when a cab blatantly ignores the ‘FILMING’ signs and almost runs then down. “Hey, I’m walkin’ here!” screams Hoffman, still in character.
What Was In The Script: The entire scene was as scripted, apart from Hoffman’s brilliant (and now iconic) response to almost being run down by a taxi.