Cameron Crowe knows how to dramatize the big job flameout: the moment that recurs in some of his movies, like Jerry Maguire and Elizabethtown — and now in the trailer for his new film, We Bought a Zoo — where the protagonist gets fired or quits and then goes out in grand style. This time, the difference is that Crowe had his own high-profile job flameout after the failure of Elizabethtown in 2005, and he hasn’t put out a narrative film in six years. Zoo, then, is his big comeback, and it’s the Americanized, fact-based story about a grieving widower (Matt Damon) who basically unplugs his life and family and moves into a zoo, where he becomes the caretaker to a menagerie of exotic animals that may include Scarlett Johansson. The trailer leans a little too hard on conventional trailer beats and Big Lines, but there’s quite a bit here that’s promising, including the presence of up-and-coming teen giantess Elle Fanning. And, also, that weird porcupine thing! What is it?