The Style Invitational is a weekly humor contest running in the Washington Post since 1993. Gene Weingarten anonymously served as the Czar until 2003, describing the contest as "the last pure meritocracy on Earth."
Week XXIV was one of my favorites, in which entrants were asked to "ruin some great line of film or literature, by adding to it."
"The best-laid plans of mice and men often go awry. Of course, mouse plans aren't that big a deal anyway." (Mike Genz, La Plata)
"Of all the gin joints in all the towns in all the world, she walks into mine. Small world, eh?" (Jean Sorensen, Herndon)
"You must ask yourself one question. Do I feel lucky? That is to say, do I, the punk, feel lucky? It's irrelevant whether I, Dirty Harry, feel lucky." (Joseph Romm, Washington)
"We'll always have Paris. Except when the Germans are using it." (Storm Marvel, Columbia)
"The horror, the horror. It really gets to me, sometimes." (Katharine M. Butterfield, Potomac)
So many more great entries in the link.
How about you, Hubski? Submit the funniest ruined line and win eternal acclaim. Feel free to recycle the tag and create your own invitational.
I got nothing, but maybe you lot will inspire me.