If you’re a Jackass fan you’ll have some idea what to expect. Johnny Knoxville disguises himself as 86-year-old Irving Zisman and takes a road trip with his 8-year-old grandson (Jackson Nicholl, who’s already an amazingly confident and gifted comic presence). They play out the simple narrative in real places with real people getting involved and reacting to the outrageous things that Zisman does. The laffs are plentiful, as long as you’re amused by gross bodily functions, genital humor and irreverent situations. Despite the craziness, Knoxville’s talent as an actor adds realism and emotion to this expedition in crazy excess. Think Jackass meets Candid Camera.