What song?

In the episode, "Gumfight at the S'Okay Corral," what song was playing at the Wild West town, and the two teams were glaring at each other? I hear a chanting as they begin to chew their gum. Then after the first gum has been (accidentally) fired, they begin the gum fight! During the (hilarious-looking) fight, the chanting continues resuming.
And by the end of the episode, you can hear it again just when it circles to black.

It reminded me of Immediate Music.
Example: http://www.youtube.com/watch?v=ZLKmbdyPlG4

For more from Immediate Music, go here:
http://www.immediatemusic.com/

Happy Birthday, Mister President
- Marilyn Monroe