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.
This Is Spinal Tap
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.
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.
The Shining
In this Stanley Kubrick adaptation of Stephen King’s novel, starred in by Jack Nicholson, a haunted hotel comes to life. Danny writes "REDRUM" on the outside of the bathroom door in the family's living quarters. When Wendy sees the word spelled in reverse in the bedroom mirror, the meaning of the word is disclosed to be "MURDER".
Jack begins chopping through the quarters' main door with a firefighter's ax. Jack breaks through the bathroom door, shouting "Here's Johnny!", but retreats after Wendy cuts his hand with a butcher's knife. The line is a reference from The Tonight Show with Johnny Carson. It wasn’t originally part of the script.
The Empire Strikes Back
Harrison Ford’s improvisation here was nothing short of genius. When Princess Leia and Han Solo are split up by Darth Vader, they kiss and Leia professes her love to Han. Ford replies to Leia’s “I love you” with an “I know.”
The film is now recognized as one of the greatest films of all time. It was at #3 on Empire's 2008 list of the 500 greatest movies of all time. To date, the film has earned more than $538 million worldwide from its original run and several re-releases.