My very favorite improv scene that Robin Williams did was on the Carol Burnett show. They did a skit wherein Robin comes to the wake of a man, Carol playing the grieving widow. They did the skit as written, and then Carol announces that Robin wanted to really do the skit "his way", and so they did it all over again, and she warned she had no idea what he had in store. Well, oh, my gosh, he was hysterical, and as the grieving widow, she had to use her hankie to stifle her laughter instead of the fake tears. She nearly fell off the sofa she was laughing so hard. He suddenly brought up "keening".......she about fell over. (a term to express loud grieving for the deceased...I have only heard it used in British or Irish wakes) and he went on and on. He was such a brilliant man....sometimes hard to control as the comedy just rolled out of him. But he sure made us laugh.......and equally, could make us cry when he did drama.