War of the Worlds sold $21 million worth of tickets in the U.S. on Wednesday, the second best Fourth of July opening ever (behind Spider-Man 2), according to Box Office Mojo.  That easily topped the Wednesday box office for Batman Begins ($15 million), but didn't even come close to the Star Wars: Revenge of the Sith first day (a Thursday) at $50 million.  

Audiences were only 52% male, with 50% over 25.  Looks like date night.