“Monsters vs. Aliens”, the 3-D film about monsters who join together to save the earth from invading aliens, grabbed the top spot at the box office this weekend, according to studio estimates from studio trackers Nielsen EDI. The animated kid’s film raked in $58.2 million in its opening weekend.

The horror flick “The Haunting in Connecticut”, based on an alleged true-life story, took second place with $23 million. Nicolas Cage’s apocalyptic thriller “Knowing” took third place and $14.7 million, marking $46.2 million in 10 days.

The buddy-romance “I Love You, Man”, took fourth place with $12.6 million. The Paul Rudd comedy has done $37 million over two weekends. Julie Roberts’ spy thriller “Duplicity” rounds out the top five with $7.56 million, lifting its total to $25.6 million.

The only other newcomer, the action film “12 Rounds”, met the low end of expectations with $5.3 million, good enough for seventh place. Final figures are due Monday.

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Box Office Grosses
Week Ending March 29, 2009

Rank Title Weekend Total Gross
1 Monsters vs. Aliens (2009) $58.2M $58.2M
2 The Haunting in Connecticut (2009) $23M $23M
3 Knowing (2009) $14.7M $46.2M
4 I Love You, Man (2009) $12.6M $37M
5 Duplicity (2009) $7.56M $25.6M
6 Race to Witch Mountain (2009) $5.64M $53.3M
7 12 Rounds (2009) $5.3M $5.3M
8 Watchmen (2009) $2.75M $103M
9 Taken (2008/I) $2.7M $137M
10 The Last House on the Left (2009) $2.61M $28.5M