AH, WILDERNESS! -- At Arena Stage through January 7.

The most exciting moment in the Fourth of July supper scene of Arena Stage's "Ah, Wilderness!" was when Nora the maid came in with a platter of lobsters. A thrill ran through the audience as people totted up the number of lobsters and how much that would cost at the wharf restaurants nearby. But then, times have changed since 1906, when Eugene O'Neill's play about happy family life in "a large small town" takes place. They haven't changed enough, however, to make convincing the atmosphere of innocence, in which generations bump ever so gently up against one another and then bob back comfortably, like boats in a basin.

Long a staple of high-school drama departments, "Ah, Wilderness!" is O'Neill's comedy -- but only by comparison with the tortured, raving, egotistical, alcoholic family life of his other plays. This one, where getting frunk is a foible that provides joke material to the family dinner table, sin is reading Oscar Wilde and everything is always forgiven with a hug, takes place in the banal time period of should-have-been. When Mama stops fussing around long enough to boast, "Mark my words -- that boy'll turn out to be a great lawyer, or a great doctor, or a great writer ," the wishfulness that created such a mama is embarrassingly obvious.

Three actors manage to come through the sappiness of the story and the pokiness of the production with some suggestions of sophistication, Mother, embryo great writer and a variety of minor characters succumb to the greeting-card personalities assigned to them, but Robert Prosky, as the father; Halo Wines as his sister, and Mark Hammer as her longtime beau bring a humor to their roles that hints of complexity beyond the stereotypes of blustering papa, spinster aunt and aging sot; they seem not to yield to the notion that just because they live conventional lives they must be naive.

Otherwise, it's pretty slow going for nearly 3 1/2 hours in that "large small town," in which most of the conversation consists of "Never you mind," and "You mustn't take on so," and "Things'll be all right, you'll see they will." If O'Neill's father the crazy drunk poetic actor had swept through town, he'd have created a sensation even bigger than the lobsters.