Even the bizarre histrionics of unfaithful family members can’t keep a good Batman down. Look for The Dark Knight to soar into the number one spot again at the box office this weekend, especially since a couple of less ambitious pics, Step Brothers and The X-Files: I Want to Believe, are opening against it. Batman does have more than a thousand-theater lead over either of the other two.

Step Brothers, a comedy about two 40-year-old men still living at home and acting like nine-year-olds, stars Will Ferrell and John C. Riley. At first they’re hate-filled rivals, but they inevitably become partners in juvenile crime when their single parents marry and move in together. Sony/Columbia has mild ambitions for this film, releasing it in about 2,800 theaters — just a little something to entertain the 18-34-year-old males who have already seen The Dark Knight four times.

Even though the franchise still has a devoted following, it’s going to be difficult for The X-Files: I Want to Believe to find a footing this weekend. The film, which has Scully and Mulder trying to solve a series of local murders and disappearances with the help of a psychic pedophilic priest, will appeal to a slightly older demographic — the same ones who didn’t want to fight the crowds to see The Dark Knight opening weekend but will probably want to see the blockbuster now that the crowds have died down. Still, it will not be a disappointing choice for the over-flow crowds — it’s playing in close to 3,100 theaters.

On a smaller scale but with a bigger heart, American Teen, the documentary that follows five Indiana high school students through their senior year, is opening this weekend in New York and Los Angeles. Some critics are calling it the best documentary of the year, if not the decade. Real teenagers who embody the stereotypes of the princess, the jock, the nerd, the heartthrob and the rebel, plus their friends, acolytes and nemeses, are studied in their natural habitat, with a bit of whimsy and animation thrown in for art’s sake. Expect a strong word of mouth campaign to draw audiences to this film, and encourage runs in more theaters across the country.