DEPENDING on your family dynamics, Thanksgiving can be a time of joyous reunions or of sheer torture. In the Lundeen household, it’s a little of both. “Things are not usually this strange around here,” says Mom (Jan Miktus) somewhat apologetically to a visiting neighbor, Jerry (N. Charles Leeder). “Oh, don’t worry about it,” he replies, adding rather matter-of-factly, “By definition, any family with three or more people is dysfunctional.” By the second act of Phil Olson’s amusing and heartwarming play, we’re inclined to agree — but dysfunctional in a nice way.

   Playwright Olson dipped into his Midwestern roots to paint this picture of family values. To understand where he’s coming from, it helps if you know the psyche of Norwegian-Americans. We (and I count myself among them) care deeply for our families and friends, but God forbid we should wear that affection on our sleeves. It would be unseemly, gauche even. If you ask us, God is Lutheran, after all.

   As the play opens, 30-something Carl (Brady Dunbar Niederer), a writer and Pillsbury truck-driver, has just arrived at the family home, where his dad (George Agalias) startles him. Dad, recently deceased, has some unfinished business he wants Carl to take care of. Ever since Shakespeare, the dead have always been butting in. But this is not Hamlet of the Twin Cities. Dad wants Carl to tell his grieving widow how much he really loved her. It’s just that he’s put it off until too late.

   Carl has problems of his own, however; talk about not showing feelings, he just broke up with his girlfriend. And Mom (Jan Miktus) is a bit hard to connect with, as she has severe short-term memory loss. Rather than a sobering affliction of old age, her disability is one of the play’s comic vehicles. Drunks are no longer acceptable sources of humor, but dementia is still high on the laugh-meter; and Mom is happily dotty. She brushes off her lapses with non-sequiturs or a cheery, “Of course!”

   Also gathering are Carl’s older brother, Michael (Barry Abramowitz), and his younger wife, Jill (Vanessa Oates), as well as their 20-something sister, Stacy (Alison Quairoli). Only Carl can see and hear Dad, who constantly prods him to act. The others are confused by Carl’s strange conversations, which are apparently to himself — “He’s got a tiny little tape recorder, with little buttons on it,” Mom explains. And so he does, for recording ideas.

   But Dad’s problem is that of everyone in this family. They don’t share their secret fears and yearnings: Michael, who seems well off, has money problems; Jill has fertility problems; and the often-ignored Stacy has two of the biggest secrets of all. As Carl says, “Discussing your feelings is not really a Lundeen trait.” At awkward moments, Mom will just smooth things over by asking brightly, “Now, who wants pie?”

   For all the serious issues this play raises — estate planning, family planning, gay rights, career choices, mental health — it does so with such a light and humorous touch that the sober and heart-tugging denouement catches us off-guard. It’s a credit to the wonderful cast, who have great lines to work with, that they juggle these opposing forces so deftly.

   I suspect that in this semi-autobiographical work, Olson is the middle son, the one who has the perspective to break through (not to mention commune with the dead; the playwright had experienced his own father’s passing before writing this). Niederer must play the straight man to Agalias’ exasperated Dad.

   The counter is Mom, whom Miktus plays in hilarious full-twang. She’s the only cast member who attempts to reproduce, and accurately, the flat Midwestern delivery that is actually in the script (“Yah” and “You betcha!” are frequent interjections. If you’ve seen the Coen brothers’ Fargo, you know the sound). But that’s all to the good. If you haven’t got a golden ear for regional accents, better not try them at all rather than try and fail.

   Robert Thick directed this little gem. It’s in a long line of family-friendly theater pieces at Off-Broadstreet that somehow slipped under the Broadway radar. Thank goodness for us that Robert and Julie Thick have an unerring eye and ear for what works best on their stage. They are able to draw in the local talent who can best present it. At their dessert-theater, the pre-show goodies are just the icing on the cake.

A Nice Family Gathering continues at the Off-Broadstreet Theatre, 5 S. Greenwood Ave., Hopewell, through Oct. 24. Performances: Fri.-Sat. 8 p.m., Sun. 2:30 p.m., with desserts served an hour before curtain. Tickets cost $27.59-$29.50; 609-466-2766; www.off-broadstreet.com