The first riddle I ever heard, one familiar to almost every Jewish
child, was propounded to me by my father:
"What is it that hangs on the wall, is green, wet -- and
whistles?"
I knit my brow and thought and thought, and in final perplexity
gave up.
"A herring," said my father.
"A herring," I echoed. "A herring doesn't hang on the wall!"
"So hang it there."
"But a herring isn't green!" I protested.
"Paint it."
"But a herring isn't wet."
"If its just painted its still wet."
"But -- " I sputtered, summoning all my outrage, "-- a herring
doesn't whistle!!"
"Right, " smiled my father. "I just put that in to make it
hard."
-- Leo Rosten, "The Joys of Yiddish"