LOS ANGELES (AP):

Moviegoers laid their money down on 21, a gambling romp that was the weekend's box office high-roller with a US$23.7 million debut, according to studio estimates yesterday.

Starring Kevin Spacey, Kate Bosworth and Jim Sturgess as math geniuses who make a killing at Vegas' blackjack tables, Sony's 21 bumped off Dr. Seuss' Horton Hears a Who! which had been number one the previous two weekends.

Horton Hears a Who!, distributed by 20th Century Fox, slipped to second place with US$17.4 million, raising its total to US$117.3 million. It is the first movie this year to pass the US$100 million mark.

Despite solid holdover crowds for Horton, overall business continued to dip. The top-12 movies took in US$90 million, down 23 per cent from the same weekend last year, when Blades of Glory was number one with US$33 million.

A strong uptick

Hollywood started 2008 with a strong uptick, but revenues have trailed off steadily since. Movie admissions had been up as much as 10 per cent in early February, but now are 2.6 per cent behind 2007's, according to box-office tracker Media By Numbers.

By this time last year, Holly-wood already had churned out a blockbuster with 300, which eventually topped US$200 million, and other hits that included Wild Hogs and Meet the Robinsons.

"Last year was very, very strong at this point. It's made comparisons very tough," said Paul Dergara-bedian, president of Media By Numbers. "We're not that far into the year, so every down weekend has a huge impact on the bottom line."

This weekend's other new movies had so-so openings. Debuting at number three with US$9.5 million was the MGM-Weinstein Co. release Superhero Movie, a spoof of one of Hollywood's favourite action genres.

Good start

Paramount's Stop-Loss, starring Ryan Phillippe as an Iraq War veteran sent back against his wishes for another tour of duty, opened at number eight with US$4.5 million.

Former Friends co-star David Schwimmer's directing debut, the comedy Run, Fat Boy, Run was a dud, taking in US$2.4 million to finish out of the top 10. Released by Picturehouse, the movie stars Simon Pegg as an out-of-shape slacker running a marathon to impress his former fiancée, played by Thandie Newton.

The audience for 21 was split almost evenly between men and women and those older and younger than 25, according to Sony.

"One of the coolest things is it really did play to everyone. It got male, female, young, old," said Rory Bruer, Sony's head of distribution.

Estimated ticket sales for Friday through yesterday at US and Canadian theatres, according to Media By Numbers LLC. Final figures will be released today.