WordNet (r) 3.0 (2006):

curtain call
    n 1: an appearance by actors or performers at the end of the
         concert or play in order to acknowledge the applause of the
         audience [syn: bow, curtain call]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "curtain call":
   act, afterpiece, bit, chaser, curtain, curtain raiser,
   divertimento, divertissement, epilogue, exode, exodus,
   expository scene, finale, hoke act, interlude, intermezzo,
   intermission, introduction, number, prologue, routine, scene,
   shtick, sketch, skit, song and dance, stand-up comedy act,
   striptease, turn