Hey, hey it’s a humorous hootenanny

The crew (led by Christopher Guest) responsible for the humor behind “This Is Spinal Tap,” “Waiting for Guffman” and “Best of Show” specializes in movies that are as savagely satiric as they are funny. But while their latest creation, “A Mighty Wind,” has its funny moments — and there are many of them — the main feeling the movie conveys is sweetness. And that makes it special. Look for the big moment between Mickey (Catherine O’Hara) and Mitch (Eugene Levy). Whaaa happenin!