The Big B.O.

...really ain't that big (at least this cycle.)

The Disney sophomore musical about high school seniors -- High School Musical 3 -- takes a -64.2% hit yet remains Numero Uno. It's $15 million gross carries it to a $61.7 million total. Not bad for a movie costing $11 million ...

The two new entries finished first and fifth in the weekend horse race.

Seth Rogan humped hard and collected $10.7 million with Zack and Miri Make a Porno ...

And The Haunting of Molly Hartley (#5) scared up $6 million.

Meanwhile, the semi-animated Bevery Hills Chihuahua (#6 ... and not declining much) has $84 million in the till.

And the fully-animated Tim Burton's Mightmare Before Christmas in StereoVision!, as perennial as The Wizard of Oz, has collected $840,000 in this, its 432nd reissue.