Movie openings ... they're not just for Fridays anymore.

With new movies tripping over each other every week as they struggle to maximize buzz and bring in more box-office bucks than the competition, studios are looking to exploit every possible edge.

Increasingly, that involves pushing at the boundaries of the traditional Friday opening - either by debuting the film just after midnight Friday (as The Dark Knight did last month) or, as is happening today with Columbia's Pineapple Express and Warner Bros.' The Sisterhood of the Traveling Pants 2, pushing Friday aside and opening in the middle of the week.

"The idea of a Wednesday opening means that you have a jump on the competition," says George Mansour, the Boston-based booker for Baltimore's Charles Theatre. "There seems to be a plethora of them right now."

The vast majority of movies still opens on Friday, and many films opening on other days of the week do so because of holiday scheduling. Studios love opening movies on Christmas, for instance, regardless of where it falls.

But today's openings mark the first of four straight Wednesdays on which a major-studio film is scheduled to debut in Baltimore. Especially during the summer, when kids are off school and don't have to worry about getting up early Thursday morning, opening some movies midweek is looking like a smart thing to do.

"It's almost like having sneak previews on Wednesday and Thursday; it builds up some momentum into the weekend," says Bert Livingston, senior vice president and general sales manager for 20th Century Fox, which is opening The Rocker on Wednesday, Aug. 20. "You get two extra days, and, hopefully, the word of mouth is good."

Not that risk isn't involved. Bad word-of-mouth can sink a movie just as surely as good word-of-mouth can keep it afloat. Open a bad movie on a Wednesday, and audiences have an extra two days to tell their friends to avoid it. Movies almost always enjoy their biggest box-office receipts on weekends, and a movie that died before its first Friday screening would be a marketing calamity of the first order.

"You have to be pretty confident of your movie to open it on a Wednesday," says box-office analyst Paul Dergarabedian of Los Angeles-based Media By Numbers. "If a movie doesn't play well on Wednesday, it's not going to play any better on Friday."

chris.kaltenbach@baltsun.com