Commedia Dell'Arte!

Commedia dell'Arte originated in Italy, around the mid-15th century. It flourished in the 16th century and was extremely popular. Commedia dell'Arte means comedy of artists. It seems to be an old form of improv. comedy. Italian theatre historians believe that commedia started as a response/reaction to the crisis and situation in Italy in the 1600's.
This form of acting, is mostly improvised, however, characters, relations, situations, etc. are all clearly outlined beforehand. Common characters that are found in Commdeia dell'Arte are Pantalone, Gratiano, Pedrolino and Arlecchino (or Harlequin), Capitano, amarosi (the lovers), villains and other characters. The performance originated in Italy, but later spread throughout Europe. Artists would perform on outside stages, with a simple set, using props to make it more detailed. Also, not to forget, each character had a mask.
Each performance was based on a general line, with the story and characters changing from troupe to troupe. There was the basic plot structure and is commonly based around two lovers, in a struggle. Over the years, actors have performed as a specific role or as a mask. Costumes are specifically worn to show the character being portrayed, along with the mask. Different props and set pieces can be used, in accordance with the general outline. Lazzi are bits and pieces of jokes, that all performers should have ready to put into any situation. There are different  lazzi's that help create different characters. An example of a lazzi  for Capitano, is him threading to beat someone up, but having an extremely long list of why he cannot do it at the current moment.
After a while, Commedia began to fade, when the best actors died, or retired. However, the spirit of Commedia dell'Arte still exists today. Although long deceased, Charlie Chaplin is among one of the funniest men of his time. In his silent films, Charlie had characters, each being very distinct, and having a specific style. Similar to in Commedia performances, (he directed his own films) he made only a general outline of what would happen throughout his performance and would improvise many different versions until he thought he had gotten it right. It is actors/comedians like him, who continue to remind us of Commedia dell'Arte.


Sources:
http://www.theatrehistory.com/italian/commedia_dell_arte_001.html
http://math.bu.edu/people/jeffs/commedia.html
http://www.humanracetheatre.org/commedia_dell'arte_AUG_7_SCREEN.pdf
Other sources are cited through Pinterest :)