Shrek Forever After easily took the weekend box office crown with an estimated $71 million, but there are plenty of indications that “the party’s ogre” for the not-so-jolly green giant, whose franchise appears to be ending none too soon.  In spite of a mammoth theater count (4,359) that includes 194 IMAX and 2373 3D screens and all those hefty ticket surcharges, the new Shrek film performed far worse than its predecessors Shrek the Third, which brought in $121.6 million in its opening frame in 2007 and Shrek 2, which earned 108 million.

After a couple of strong weeks, the total gross of the top ten films was down 15.7% from the same weekend last year when Night at the Museum: Battle of the Smithsonian opened with $54.2 million, and down 14.8% from 2008 when Indiana Jones and the Kingdom of the Crystal Skull debuted with $100.8 million.  Look for the box office to bounce back next weekend with Sex in the City 2 and Prince of Persia opening.

It’s hard to characterize a $71 million opening as a bit of a failure, but given the sterling record of the Shrek franchise (Shrek 2 earned $441.2 million), even with audiences giving Shrek Forever After an “A” Cinemascore, the final Shrek film will likely finish as the lowest grossing film in the franchise.

Meanwhile Iron Man 2 dropped 49% in its third weekend as it earned $26.6 million, which brings its domestic cumulative to $251.3 million.  The original Iron Man earned $31.8 million in its third frame and had a cumulative of 223.1 million after 17 days of release.  Iron Man 2 looks like it could have some trouble matching the original Iron Man’s $318 domestic gross, but it has already matched the original’s overseas total of $266 million, and will likely come very close to the first film’s worldwide total of $585.1 million.

Universal’s Robin Hood fell 48% in its second weekend and finished in third place with an estimated $18.7 million.  Ridley Scott’s Sherwood Forest epic appears certain to top $100 million domestically and will do even better overseas.

Two romantic comedies that debuted last week, Letters to Juliet (down just 32%) and Just Wright (down 49%) finished in the fourth and fifth spots respectively. 

The Saturday Night Live-based MacGruber, which stars Will Forte and Kristen Wiig, posted one of the worst openings ever for a film debuting in more than 2,500 theaters.  The skit-based movie, which is an extended take-off on the MacGyver TV series, earned just $4.1 million in its first weekend in spite of a major TV advertising campaign.  With a dismal CinemaScore of “C-“and a pitiful average of just $1,607 per theater, MacGruber is a “bomb” that even its erstwhile hero show no sign of being able to defuse.

In its 7th weekend the Steve Carrell/Tina Fey comedy Date Night fell just 26% and brought its cumulative to over $90 million.  It appears more and more likely that Date Night will manage to top the $100 million mark though it may take three months to do so.

An even bigger long-running hit, Dreamwork’s 3D animated How to Train Your Dragon came in a #9 during its 9th weekend in theaters.  Dragon has earned $210.9 million and Shrek Forever After may well end up in the same neighborhood.

The number 10 film was the Bollywood crossover title Kites, which was shown in only 208 theaters, but averaged nearly $5,000 per venue.