Berlioz: Symphonie Fantastique- 5th Movement

Fifth movement: "Songe d'une nuit de sabbat"(Dreams of a Witch's Sabbath)

From Berlioz's program notes:

He sees himself at a witches’ sabbath, in the midst of a hideous gathering of shades, sorcerers and monsters of every kind who have come together for his funeral. Strange sounds, groans, outbursts of laughter; distant shouts which seem to be answered by more shouts. The beloved melody appears once more, but has now lost its noble and shy character; it is now no more than a vulgar dance tune, trivial and grotesque: it is she who is coming to the sabbath… Roar of delight at her arrival… She joins the diabolical orgy… The funeral knell tolls, burlesque parody of the Dies irae, the dance of the witches. The dance of the witches combined with the Dies irae.

The return of the idée fixe as a "vulgar dance tune" is depicted with a prominent E-flat clarinet solo. There are a host of effects, including eerie col legno playing in the strings, the bubbling of the witches' cauldron to the blasts of wind. It is important to remember that Berlioz's use of the word "orgy" pertains to a cultic gathering and not the more modernized meaning. The climactic finale of the symphony combines the somber Dies Irae melody with the wild fugue of the Ronde du Sabbat (Sabbath Round).

From: http://en.wikipedia.org/wiki/Symphonie_fantastique#Fifth_movement:_.22Songe_d.27une_nuit_de_sabbat.22.28Dreams_of_a_Witch.27s_Sabbath.29