During an interview in 1994 on Inside the Actor’s Studio, Williams made an audience member laugh so hard that he had to be taken away by an ambulance. The audience member had incurred a hernia from the laughter!

Robin Williams is a Chicago native and is a comedian/actor known for his great improvisation skills. Some of his work includes Mrs. Doubtfire and Patch Adams. Image: 

(Sources 1, and 2)