"Tropic Thunder" still thundering!

LOS ANGELES (Reuters) - Action movie spoof "Tropic Thunder" commanded the No. 1 spot at North American box offices for the second straight week, narrowly conquering sorority-themed college romp "House Bunny."

"Tropic Thunder," which stars Robert Downey Jr, Ben Stiller and Jack Black, had an estimated weekend total of $16.1 million at U.S. and Canadian theaters, bringing its total domestic take to $65.7 million, according to studio estimates on Sunday.

Downey, Stiller and Black have won much laughter from audiences playing a group of self-absorbed Hollywood actors caught up in a real-life battle with narco-terrorists while filming a war movie in Southeast Asia. The film was directed, co-written and co-produced by Stiller and was distributed by Paramount Pictures, a unit of Viacom Inc.

"House Bunny," from Sony Corp's Columbia Pictures unit, debuted at No. 2 with ticket sales of $15.1 million.

Written by Kirsten Smith and Karen McCullah Lutz of "Legally Blonde" fame, the comedy stars Anna Faris as a former Playboy playmate who becomes house mother to socially inept sorority sisters after being cast out of the Playboy mansion.

In third place was "Death Race" with a weekend tally of $12.3 million, according to a spokesman for Universal Pictures, a unit of General Electric Co's NBC Universal.

The film, loosely based on 1975's "Death Race 2000," stars Jason Statham as a former Nascar champion and ex-con who is framed for his wife's murder and forced by a prison warden to compete in a brutal winner-take-all race of weaponized monster cars. Joan Allen stars as the icy prison warden.

The blockbuster Batman sequel "The Dark Knight" slipped from last week's No. 2 slot to No. 4 as ticket sales tumbled 37 percent to $10.3 million.

"The Dark Knight," a Warner Bros release, has amassed more than $489 million in six weeks of domestic ticket sales and is the second-highest grossing domestic film ever behind "Titanic."

Warner Bros' animated "Star Wars" movie, "Star Wars: The Clone Wars," rounded out the top five with an estimated $5.7 million in North American ticket sales.

"Pineapple Express," a stoner comedy named for a strong type of marijuana, stoked box offices with $5.6 million in sales in its third week, while the American remake of the South Korean horror film "Mirrors," starring Kiefer Sutherland of the hit TV series "24," grossed $4.9 million in its second week to land in the No. 7 spot.

"The Longshots," based on the real-life story of 11-year-old Jasmine Plummer -- the first girl to compete as a quarterback in the Super Bowl of Pop Warner football, squeaked past "Mamma Mia!" in its first week in theaters with $4.3 million in ticket sales.

Lumbering in at No. 10 with $4.1 million in sales was Universal's "The Mummy: Tomb of the Dragon Emperor."