You know the one: dat da da da dat da da da CHARGE!!!!
(http://www.youtube.com/watch?v=vb19d08Lnec)

Got a little curious and found:

Re: History of "Charge" Song.
The "Charge" song that everyone associates with baseball games was created by Tommy Walker in 1946. Tommy Walker was a junior at USC . The USC football team was in need of a lift that season, so he wrote a six-note fanfare for the trumpet section: "Da da da DUT da DUH!" Trojan rooters then screamed, "Charge!"

The "Charge" song/chant became famous when the Dodgers moved from Brooklyn to Los Angeles in 1958 and began to use it.

URL: http://able2know.org/topic/86304-1

There seems to be some insistence that it is from a military bugle call that goes back 100 or 2 years farther back.

Anyone have any additional thoughts on this?