Judd Apatow scored his second success as a producer this summer with the teen comedy “Superbad,” which debuted at No. 1 in the North American box office, with $31.2 million.

“Knocked Up,” starring Katherine Heigl and Seth Rogen, was Judd Apatow’s first box office hit this summer, in early June. He co-wrote the script with Rogen, as he did again with “Superbad.”

Rogen also co-stars in “Superbad,” a teen comedy that debuted as this weekend’s top movie at the North American box office, with $31.2 million. The movie follows the adventures of two awkward high school boys interpreted by Michael Cera and Jonah Hill, in their quest to obtain alcohol for a party and impress their love interests.

Judd Apatow, 40, also has “The 40-Year-Old Virgin” to his credit, a 2005 comedy starring Steve Carell, which Apatow wrote, directed and produced.

As moviegoers crowded to see teenagers make silly, endearing fools of themselves, last week’s number one movie, “Rush Hour 3,” starring Jackie Chan and Chris Tucker, slipped to the number two position, with $21.8 million.

“The Bourne Ultimatum,” starring Matt Damon and Julia Styles, was No. 3 with $19-million. At No. 4, we find “The Simpsons Movie,” with ticket sales worth $6.7 million.

The long delayed “The Invasion,” starring Nicole Kidman and Daniel Craig, made its debut at No. 5, with a modest $6 million.

“Stardust,” released a week ago and featuring an ensemble cast which includes Charlie Cox, Claire Danes, Michelle Pfeiffer and Robert De Niro, slipped to the number six position, with $5.2 million, while John Travolta’s “Hairspray” slid to number seven, with $4.3 million.

Rounding up the weekend’s top ten movies at the box office were “Underdog,” with $3.6 million, “Harry Potter and the Order of the Phoenix,” with $3.5 million and “I Now Pronounce You Chuck and Larry,” with $3.5 million.

These preliminary figures are studio estimates.

Other movies to debut this weekend are “The Last Legion,” starring Colin Firth, Ben Kingsley and Aishwarya Rai, with ticket sales worth $2.6 million; British black comedy “Death at a Funeral,” starring Matthew Macfadyen and Rupert Graves, with $1.3 million; and “The 11th Hour,” an ecological documentary featuring the narrating talents of Leonardo DiCaprio, with $56,000.