LOS ANGELES (Reuters) - Hapless martial arts hero Jackie Chan knocked amnesiac assassin Jason Bourne out of the top spot at the box office this weekend.

"Rush Hour 3," the buddy film starring Chan and Chris Tucker that comes six years after the duo's last romp, grossed $50.2 million in its first weekend at U.S. and Canadian theaters.

"The Bourne Ultimatum," the third installment of the espionage action series starring Matt Damon as a one-time CIA hit man searching for his past, took in $33.7 million in its second weekend playing in North American theaters, a 51 percent drop, according to studio estimates on Sunday.

Animated feature "The Simpsons Movie" dropped 56 percent in its third weekend to $11.1 million, but pot-bellied anti-hero Homer Simpson still came out on top of two newcomers.

In their first weekends, "Stardust," a fantasy film starring Claire Danes, grossed $9.0 million at number four on the charts, and "Daddy Day Camp" took in $3.6 million and debuted at number 10.

The long delay since the last "Rush Hour," was seen as a challenge for Tucker and Chan. "Rush Hour 2" set a record August opening of $67.4 million in 2001, which held until last week, when "The Bourne Ultimatum" took in $69.3 million.

"Rush Hour 3" was released by New Line Cinema, a unit of Time Warner Inc. "The Bourne Ultimatum" was released by Universal Pictures, a unit of General Electric Co.'s NBC Universal Inc.

"The Simpsons Movie" was released by 20th Century Fox, a unit of News Corp., "Daddy Day Camp" was released by TriStar Pictures, a unit of Sony Corp., while "Stardust" was released by Paramount Pictures, a unit of Viacom Inc.