Alfred Kahn, an economic advisor to Jimmy Carter, upset the president and his cabinet by stating that the country’s huge inflation could lead to a recession, or even "deep, deep depression." He was chastised for this assessment and told that words like "recession" have a very negative connotation and poor political implications. Unfazed, Kahn told the cabinet that he would use the word banana instead, as in "Between 1973 and 1975 we had the deepest banana that we had in 35 years." However, after banana companies started to complain he changed the word to kumquat.

Sources:
http://www.interalia.org/archives/000202.php
http://www.nationalreview.com/comment/comment-krikorian090401.shtml