Source : Webster's Revised Unabridged Dictionary (1913)

Extravaganza \Ex*trav`a*gan"za\, n. [Extravagance with an
   Italian ending: cf. It. stravaganza.]
   1. A composition, as in music, or in the drama, designed to
      produce effect by its wild irregularity; esp., a musical
      caricature.

   2. An extravagant flight of sentiment or language.

Source : WordNet®

extravaganza
     n : any lavishly staged or spectacular entertainment