Movie 1: Brother Bear "Bucky not Binky"
In this scene the little bear (Koda) is annoying the big bear (Kenai). While they were acting out their line Juaquin Phoenix (who voiced Kenai) accidentally said the wrong line, but Jeremy Suarez (who voiced Koda) came up with a comeback.
Movie 2: Alice in Wonderland 'Mad Tea Party'
Before they started animating the movie, they first preform it live with the actors then have them models for the animators. In this mad tea party this interaction was improved so that the actors can create some sort of madness to their characters.
Movie 3: Aladdin 'The Genie'
This movie contains a lot of improve from Robin William each time they record many of his impressions for each line and there was a lot of recording. The animators had so much fun animating all of Robin's takes but it was also difficult and a lot money into this project.