Commedia dell'arte
The commedia dell'arte is a form of comedy that appeared during the sixteenth century in Italy. The original commedia seems to have been a form of improvised comedy, usually associated with some sort of mountebank (huckster), though later in the century they went legit.
For about ten years, I was a not-quite-founding member of I Sebastiani, a commedia dell'arte troupe in the Boston area. My first perfomance was their third, and I stayed with the troupe until we left the Boston area in 2002.