In the 21 December 2009 issue of the New Yorker Magazine, Paul Rudnick’s article, Holly or Challah? gives “some tips to help the sensitive Christian make everyone, no matter what they’re wearing on their head, feel at ease and have a Happy Interfaith Holiday Season!”
Amusing.
-RichardH
Great humor. The people I know who need to read it most would probably not understand it, though.
Maybe that’s why the phrase was invented.