There was a commercial for the US Marine Corps about 10-15 years ago
that featured a life size chess board with real horses and knights
etc...  There was a piece of classical music playing in the background
of the commercial which I want to identify.  Please identify this
score for me.

Although the music sounds classical, and resembles portions of Carl
Orff's "Carmina Burana," it was apparently composed specifically for
the commercial.

These newsgroup posts may be of interest:

">What is the music in the Marines commercial where there are human chess 
 >players? 

i once called the marines about this and was referred to their
advertising agency in atlanta. it's an 'original' composition by a
composer the agency regularly uses and is not (or at least wasn't two
years ago) available in any form; besides, it's only 30 seconds long.
i write 'original' because there are obvious classical influences. you
might want to start with orff's 'carmina burana' and go one from
there."

http://groups.google.com/group/rec.music.classical/browse_thread/thread/f6c246440570c9ae/26b75498790d8d4e?lnk=st

"A few years ago, I spent an afternoon here at the paper making calls
to find out where that music is from. I eventually ended up talking to
the folks at some ad agency in Atlanta that handles the Marine Corps
account. According to the person I talked to, the music, an original
composition obviously inspired by Carmina Burana, was written
specifically for the commercial by some no-name ad jingle writers that
the agency uses. To boot, the music is no longer in duration than what
you hear on TV. At the time I called, the music was unavailable in any
form."

http://groups.google.com/group/rec.music.classical/browse_thread/thread/5a92c6cc464738c7/aaf76dc501f2ee3f?lnk=st