David McKie has a fun little piece in the Groan. Worth reading. As part of this blog’s policy of outsourcing  where there is a comparative advantage I am able to sum up the piece for you. The Joy of Knitting very kindly provided the full version of a half remembered phrase.

"L’ospite è come il pesce. Dopo tre giorni puzza."

Much other good stuff at Ms. Knit’s place, although not a translation of the phrase, which you’ll have to work out for yourself.