If you're looking to get into a fizzy, happy mood, the opening credits of My Blue Heaven featuring idyllic drawings of suburbia and Fats Domino barking the title song over an irresistible, chugalug beat will do the trick. The movie itself, with the exception of a few scenes, doesn't really have the wit it's aiming for, and among Steve Martin vehicles it's middle-drawer, at best. Yet that mood of silly exuberance reigns through most of the picture.
Martin plays Vinnie Antonelli, a New York mobster who, under the federal witness-protection program, has been hidden in Fryburg, a California suburb full of identical tract houses; the place is so prefab anonymous that the moment Vinnie arrives, his wife leaves him to go back to the city. Rick Moranis is Barney Coopersmith, the pencil-pushing FBI agent overseeing Vinnie's case. Barney's wife has left him as well, and the movie is about how the two men become friends: The dapper Vinnie gets Barney to relax and, you know, live.
This is the third movie within six months to feature a cartoon Italian stud. Kevin Kline in I Love You to Death was mischievous and operatic. Anthony LaPaglia in Betsy's Wedding was absurdly formal a Damon Runyon burlesque. And Martin? He's the weirdest one yet. It's as though he were doing a standard parody of an Italian gangster and, at the same time, holding back, so that he could still be ''Steve Martin.'' Vinnie, with his moussed swatch of finger-in-the-light-socket hair, is a comedy-sketch mutant a WASP soaked in garlic. The fun of Martin's acting here is its florid physicality. Vinnie is a man who literally glides through life. When he sees a woman who attracts him (one of the funnier moments is his seduction, in the frozen-food case, of a hot-to-trot suburbanite played by Carol Kane), he's all floating instinct. Even the lust in his eyes seems ethereal.
Vinnie spends most of the movie committing petty crimes and eluding the clutches of the prim, scolding Fryburg DA (Joan Cusack, in a not-so-great role). The script, by Nora Ephron (When Harry Met Sally ), is tame, predictable, and mostly a skeleton for the performers. Rick Moranis' Barney is a cuddly straight-arrow too earnest to connect with women. My Blue Heaven becomes a standard nerd-lets-go-of-his-inhibitions comedy, with Vinnie showing Barney how to dance, how to approach women with confidence, how to trade in his abominable, Sears-catalog wardrobe for silk suits. But what he really teaches Barney is lightness.
The movie's high point is a nightclub dance scene in which the two do the merengue. Director Herbert Ross (Steel Magnolias) is a former choreographer, and what's exhilarating about the scene is that you can practically feel him saying ''What the hell!'' and shooting the works. The movie, which until then has seemed a little repressed, suddenly breaks free. Martin has always been a master of this sort of thing he gets high on balletic nonsense. The surprise is Moranis, whose dancing has a spry goofiness. Barney is much more fun to watch after he loosens up (in part because he remains slightly goofy). Moranis, who looks like a sad, intellectual gopher, will always be limited by his appearance, but My Blue Heaven suggests he's witty enough to break out of the straitjacket of playing geeks and losers. He's a character actor with a great many more characters in him. B-