Sid Caesar, with Imogene Coca, on the "Show of Shows" of early TV (1950-1954), pioneered the comedy sketch. He launched Mel Brooks, Woody Allen, Carl Reiner, Billy Crystal and others.
Show of Shows was 90 minutes of live original sketch comedy, broadcast each Saturday night.

Woody Allen called him one of the truly great comedians.
The quality of his sketches has seldom been equaled.

Like several others, he got his start on the borscht circuit in the Catskills.

An example of his sketches, The Recital, may be seen on youtube.