As predictable as a pile of unwanted catalogs in my mailbox, November brought with it an ad for a community “Holiday Celebration.” Which holiday? Is it possible that my Denver suburb will be celebrating Pancha Ganapati, the five-day Hindu festival in December honoring Ganesha? Possible, but unlikely. A choir probably will not be singing pagan Yule or Saturnalia songs at the event, although they might devote a tune to Hanukkah amid the…