"Charge!" with the bugle call comes from the movie ARSENIC AND OLD LACE.
The movie came out during WWII. One of the characters thinks he's Teddy Roosevelt, and is continually charging up the stairs blowing a bugle, yelling "Charge!", thinking that he is leading the Rough Riders up San Juan Hill.
After the movie came out crowds at Dodger games started doing it.
At least, that is the story that the director, Frank Capra tells in his autobiography THE NAME ABOVE THE TITLE.


Mark Ross