Right now you can see Jackass Presents: Bad Grandpa in theaters, and while it doesn't have the same fast-pace and super outlandish pranks from the real Jackass franchise, it's still an entertaining comedy. The narrative is an interesting addition to the candid camera style pranks, but it definitely slows down the film. Of course, it doesn't make their achievement any less impressive, and you might find yourself wondering just how they did it. Thankfully, there's a cool behind-the-scenes featurette that shows how they set up marks to sell a given prank to the real people, and also Johnny Knoxville's awareness when stuff goes awry. Here's the featurette for Jackass Presents: Bad Grandpa, from Vice: Jackass crew member and film franchise director Jeff Tremaine is at the helm of Jackass Presents: Bad Grandpa, which he co-wrote with Preston Lacy. 86 year-old Irving Zisman (Johnny Knoxville) is on a journey across America with his 8 year-old grandson Billy,...