There was a time in baseball history when baseball clowns would perform before or during or after games.
Perhaps the most famous clowns were Al Schacht, the Clown Prince of Baseball, and Nick Altrock, who formed a partnership for part of their careers. Max Patkin was a notable baseball clown from the 1940s until the 1990s. Clowns were also common in leagues other than the Major Leagues - Spec Bebop and King Tut were very popular in the Negro Leagues during the same period that Schacht and Altrock were active, while Country Brown was known as "Al Schacht the second" for his shtick from the coaching box.
There were also clown teams, such as the Indianapolis Clowns.
One Source: Clowns of Baseball.