The Collaborative International Dictionary of English v.0.48:

Festive \Fes"tive\, a. [L. festivus, fr. festum holiday, feast.
   See feast, and cf. Festivous.]
   Pertaining to, or becoming, a feast; festal; joyous; gay;
   mirthful; sportive. -- Fes"tive*ly, adv.
   [1913 Webster]

         The glad circle round them yield their souls
         To festive mirth and wit that knows no gall. --Thomson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

festive
    adj 1: offering fun and gaiety; "a festive (or festal)
           occasion"; "gay and exciting night life"; "a merry
           evening" [syn: gay, festal, festive, merry]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "festive":
   blithe, blithesome, boon, convivial, festal, free and easy, gala,
   gay, gladsome, gleeful, hail-fellow-well-met, hearty, hilarious,
   jocund, jolly, jovial, joyful, joyous, lighthearted, merry,
   merrymaking, mirthful, on the loose