Raiders Of The Lost Ark
Harrison Ford is just incredibly gifted at improvisation and there’s nothing we can do but to be thankful for it. After all, it is this skill that gave us one of the most epic fight scenes in movie history. It might have been played for laughs, but the Raiders of the Lost Ark battle was actually meant to be a serious duel. However, Ford got sick before they were due to shoot and he was thus unable to perform the fight choreography. The crew was able to find a way to make the scene easier for the actor and the rest is history!
Raiders Of The Lost Ark
RoboCop
It is also possible to clue the director in when one actor plans on improvising. They can plan together to keep the others clueless about a change in the strict so the camera can capture real emotion. This was the case when Kurtwood Smith informed the director about something he wanted to do. That’s why everyone seemed genuinely surprised when Smith demands, “Give me my fuckin’ phone call.”
RoboCop