10 Biggest Valentine's Day Weekend Openers: Hearts, Horror and Horrible Superhero Movies (Photos)

History tells us hearts-and-flowers films like “The Vow” and “Hitch” can carry the Valentine's Day box office, but so can movies about monsters, murderers and Marvel superheroes.

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10.) "Percy Jackson & The Olympians: The Lightning Thief": This young adult novel adaptation grossed over $31.2 million its first weekend in theaters when it was released Feb. 12, 2010.