We have here a scene from
The Lord of the Rings: The Two Towers film, when the defenders of Helm's Deep are confronting the attacking orcs. The attackers are playing the Onyx song
Slam (1993), which the defenders don't like very much:
http://www.youtube.com/watch?v=1O3i29LEcX8
Things begin in earnest at 1.04, with the punchline at 1.38.