Vaudeville! The Library of Congress has a great selection of available recordings, films and other information about that lost form of entertainment, the vaudeville stage. You can listen to The Arkansas Traveller, a comedy sketch that dates back to at least 1852! A Laughing Sketch, there were lots of these. It was basically a sketch where something happened and someone with an infectious laugh started laughing until everyone on stage and the whole crowd joined in on the mass hysteria. Or just enjoy a dramatic reading like this one.
They don’t have video collection online, but if you find a title you like in their archive, search youtube, I found Animal Act With Baboon, Dog and Donkey.
There are also scanned scripts available. The featured script right now is The Lone Hand Four Aces (To be acted by a Troupe of Educated Dogs). Most of the scripts read as if they are transcribed from someone describing the stage act to someone else. Which they probably were. Scripts in English and Yiddish.
Perfect for research, inspiration and entertainment.