The Collaborative International Dictionary of English v.0.48:

Phantasmagoria \Phan*tas`ma*go"ri*a\, n. [NL., from Gr.
   fa`ntasma a phantasm + 'agora` an assembly, fr. 'agei`rein to
   gather: cf. F. phantasmagorie.]
   1. An optical effect produced by a magic lantern. The figures
      are painted in transparent colors, and all the rest of the
      glass is opaque black. The screen is between the
      spectators and the instrument, and the figures are often
      made to appear as in motion, or to merge into one another.
      [1913 Webster]

   2. The apparatus by which such an effect is produced.
      [1913 Webster]

   3. Fig.: A medley of figures; illusive images. "This mental
      phantasmagoria." --Sir W. Scott.
      [1913 Webster]

WordNet (r) 3.0 (2006):

phantasmagoria
    n 1: a constantly changing medley of real or imagined images (as
         in a dream)

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "phantasmagoria":
   apparition, appearance, cosmorama, cyclorama, diorama, display,
   eidolon, exhibit, exhibition, exposition, fantasy, figure, form,
   georama, idolum, image, light show, myriorama, pageant, pageantry,
   panorama, parade, phantasm, phantasma, phantom, pomp, presence,
   presentation, psychedelic show, representation, shade, shadow,
   shape, shifting scene, show, sight, spectacle, specter, stage show,
   tableau, tableau vivant, vision, waking dream, wildest dream,
   wraith