This hilarious comedy about the made-up rock band Spinal Tap was full of improvisations, so much that the three lead actors received credit for writing the film. Rob Reiner recorded hours of improvised lines, and it proved to be difficult to cut the footage down.
The improvisation actually started years before in the late 1960s when Michael McKean and Christopher Guest first met during college and played music together. They worked with Harry Shearer and Rob Reiner on a TV pilot in 1978 for a sketch comedy show called The TV Show, which featured a parody rock band called Spinal Tap. During the production of the sketch, McKean and Guest began to improvise, and thus came to life the characters that became David St. Hubbins and Nigel Tufnel.
A Clockwork Orange
In a futuristic Britain, Alex DeLarge is the leader of a gang. One night, after getting inebriated on drug-laden "milk-plus", they participate in an evening of "ultra-violence", which includes a fight with a competing gang led by Billyboy. After not being happy with a number of takes, Stanley Kubrick told Malcolm McDowell, who played the character, Alex, to do whatever he wants.
This welcomed the stunning improvisation of McDowell who started to sing “Singing in the Rain” during a terrifying scene, making him seem all the more crazy.
Saving Private Ryan
In this classic Steven Spielberg war movie, during a scene in which Tom Hanks as Captain Miller and Matt Damon as Private Ryan talk about their lives at home, Matt Damon completely makes up the story about catching his brother kissing a girl. The film received critical acclaim and praise was given to Spielberg for his directing while the actors, particularly Tom Hanks were recognized for their performances.
The film was the second-highest-grossing film of 1998 worldwide. The film’s success once again was confirmed by the 71st Academy Awards, in which it received 11 nominations and won five of them including Spielberg's second win for Best Director, Best Film Editing, Best Cinematography, Best Sound Mixing, and Best Sound Editing.
Dr. Strangelove
This satire covers the paranoia surrounding the threat of nuclear war. Otherwise known as How I Learned to Stop Worrying About The Bomb, the script was made up of a collection of ad-libs put together over time. Of these improvs was Peter Sellers’ Dr. Strangelove’s inability to control his right arm, which naturally became a Nazi salute
Sellers is noted for improvising a lot of his dialogue, with co-writer Stanley Kubrick adding the ad-libs into the written screenplay so that his improvised lines became part of the official screenplay, a practice known as retro scripting.
Zoolander
In this classic comedy, Ben Stiller plays Derek Zoolander, a dimwitted, narcissistic male model who becomes duped by corrupt fashion executives who are plotting to assassinate the Prime Minister of Malaysia. Stiller brilliantly improvises by repeating a line he had previously recited “Why male models?” He hadn’t planned on repeating the line, but it made his ridiculous persona even more foolish.
David Duchovny, being the talented actor he is (he played the character, J.P. Prewitt) totally went with it. While Zoolander 2 was less of a success, that scene is undoubtedly one of the funniest moments in the film.