Will Ferrell and John C. Reilly take the plunge into a pool of raunchy comedy in “Step Brothers.” Columbia Pictures photo

Opening Friday “Step Brothers” R, 1:52, Kaahumanu 6 and Front Street Theaters. Will Ferrell and John C. Reilly team up in the title roles as two 40-year-olds with arrested development issues — they both still live at home with their single parents, Mary Steenburgen and Richard Jenkins. Imagine their shock when they wind up having to share a bedroom after their parents get married. They spend the rest of the film trying to one-up or out-gross each other in a string of hopefully funny situations, directed by Adam McKay, who co-wrote the story with the bros. “The Visitor” PG-13, 1:48, Kukui Mall 4. A hit at June’s Maui Film Festival at Wailea (Maui Film Festival will show it again Aug. 13 in Castle Theater at the MACC), this tender dramedy features Richard Jenkins as a bored economics professor still mourning for his wife who travels to New York where he becomes involved with an illegal immigrant couple. Before he knows what’s happening, he’s drumming on a West African djembe