It looks like Mike was on to something when he asked if Speed Racer would be this year’s first official Flopbuster. We reported late Friday night that the number for Speed Racer weren’t looking good. A lot depended on the Saturday numbers, but they weren’t good either.

The WB went on to embarrass themselves on Sunday by overestimating their box office take by nearly $2M. They were estimating Speed Racer had grossed around $20.5M which put them just over What Happens In Vegas for second place. When the final studio figures came out yesterday, however, Speed Racer fell to third with a take of only $18.5M while What Happens In Vegas finished with $20.1M.

To say that Speed Racer is a colossal disappointment would be the understatement of the year. People have been trying to get this movie made for years. They finally got it made, by a pair of star directors no less, only to see the movie tank in it’s opening weekend. Overseas numbers weren’t nearly as high as the studio had hoped either. To make matters even worse, this weekend will bring The Chronicles of Narnia: Prince Caspian as direct competition and that film is already tracking to hit somewhere in the mid-$60 to $70 million range. Speed Racer is definitely going to have a hard time recouping its cost.

A film that’s not going to have a hard time recouping its cost is Iron Man which went on to score another $51.2M over the weekend dropping only 48% from last week (which is good considering how much business it did the first week). The cumulative total for Iron Man has soared to $177.8M already making it the top grossing film of 2008 by surpassing the $150.7M that Horton Hears A Who has collected over the last two months.

Led by the voice talents of Jim Carrey and Steve Carell, the film opened in 3,954 locations and averaged a healthy $11,406 per theater. The film generated the fourth best March opening ever behind 300 ($70.9M), Ice Age: The Meltdown ($68M), and the original Ice Age ($46.3M). Dr. Seuss’ Horton Hears a Who! also landed the fifth largest opening in history for a G-rated film.

“It’s a who-mongous opening,” Fox senior VP of distribution Chris Aronson said. “Blue Sky has made a film that makes you feel like you are immersed in the pages of Dr. Seuss’ world. It is colorful and vibrant, and so true to his work.

The film, based on Dr. Seuss’ 1954 book of the same name, cost roughly $85 million to produce and marks Jim Carrey’s first starring voice role in an animated film. Industry insiders were are abuzz about the fact that the film nearly matched the opening of Ice Age despite its G rating. Generally speaking, G-rated films can be risky as older kids and teens sometimes see these films as being more for children. Horton, however, saw 47% of its audience come from non-family with teens being the largest segment of that percentage (40%) putting this Fox film on par with Disney/Pixar films.

Disney and Pixar, of course, have been the exception to the rule. Their films generally appeal to all audiences regardless of rating. Disney/Pixar, in fact, boasts the top four G-rated animated films in terms of opening weekend: Finding Nemo ($70.2 million), Monsters, Inc. ($62.6 million), Cars ($60.1 million) and Ratatouille ($47 million). All except Monsters, Inc., which debuted in November, opened in the summer.

Horton, however, couldn’t match the opening of the Dr. Seuss/Jim Carrey starrer Dr. Seuss’ How the Grinch Stole Christmas, which opened to $55.1 million in 2000. Horton did beat Mike Myers starrer Dr. Seuss’ The Cat in the Hat, which debuted to $38.3 million. Neither of those two Dr. Seuss films were animated.