Contrary to various dire predictions that Michael Moore’s “SiCKO” was destined for a dismal showing at the box office, the cinematic indictment of U.S. health care is now the fifth top-grossing documentary of all time, joining a list that also includes Moore’s previous docs “Farenheit 9/11” and “Bowling for Columbine.” To celebrate, Moore’s announced a contest called “SiCKO Night in America,” a contest open to all who attend the movie this weekend, in which the grand prize is an all-expense-paid trip for two to their choice of London, Paris or Toronto — and an opportunity to see firsthand how a universal health care system operates. A nice opportunity for those who doubt the veracity of Moore’s claims to throw their hats in the ring to find out for themselves, perhaps…