Family matters 700 Sundays, Tuesdays with Morrie, A Number BY CAROLYN CLAY

Fernando looks positively Chaplinesque. In his sentimental but herculean entertainment 700 Sundays (at the Opera House through October 29), comedian and movie star Billy Crystal shows off a skill for physical comedy that tilts at the silent-film greats. (In fact, the work includes a soundless home movie performed live.) He also gets to tell the fascinating story of a Long Island youth lived in the shadow of the jazz legends recorded by his family’s Commodore label, commemorate his ebullient Jewish relatives, send a valentine to a dad who died too young, carry on an agitated conversation with his apparently basso penis, and call George W. Bush "President of the Dukes of Hazzard."

Part stand-up, part memoir, 700 Sundays had a six-month Broadway run and won Crystal a 2005 Tony for Best Special Theatrical Event. The three-hour show could be called indulgent, but it’s also sweet — and living proof of a connection between showmanship and ADD. When the 58-year-old Crystal blithely mirrors the tap routine performed on a screen behind him by his five-year-old doppelgänger, who’s caught by his dad’s 8mm camera sporting an eager grin and a boutonnière, you understand how hams are born and bred but never cured.

As the young Crystal observed on his first outing to the Catskills, where "the comedian was king," he "could do that!" And indeed he can, not just batting one-liners the way he did his pitcher father’s curveballs but creating Lily Tomlin–esque plays within the play, among them barking Boca Raton matron Aunt Sheila’s telephone call to a friend with the news of her daughter’s "lesbyterian" wedding. With the real McCoy beaming larger than life above him, Crystal’s Sheila moves stiffly on her titanium hip, never letting go the cigarette clenched between two fingers, even as her whole hand does a graceful dance to convey the dreamy pleasure of her husband’s waltz from consternation to tolerance.

Des McAnuff, artistic director of La Jolla Playhouse, where Crystal honed the act that would become 700 Sundays, helms the work, which gets a visual boost from the old photos and home movies that materialize in the windows of the set — a replica of Crystal’s modest but happy childhood home. And from the moment the star bursts through the door in stretchy black pants and gray crew top, he’s as fast as the montage of memories flashing behind him, getting his putty face around a taciturn grandfather whose conversation was made percussive by the farts he couldn’t hear; facially paralyzed "Uncle Picasso," who told his wee nephew filthy jokes; and the whole loving, gesticulating clan epitomized by the barbecue-king uncle whose burger-flipping journey from bonhomie to fury Crystal turns into a silent, jerky aria.

The surety of Crystal the performer (who had not worked live for 15 years when he undertook this project) is nowhere better attested than in the second act, which quickly arrives at the end of what the performer judges to have been the 700 Sundays the family shared with father Jack before he died of a heart attack while bowling. Crystal does not stint on the emotional devastation this wrought on his 15-year-old self. But no sooner is he feeling his distraught mother’s "warm tears running down my cold face" than the clan is subject to a lisping funeral director he cannot help but equate with Sylvester the Cat. Inserting a spit-riddled "I t’ought I taw a puddy cat" into the Jewish prayer for the dead is proof that, however somber the occasion, you cannot keep a good joke down.

The Odd Couple meets Elisabeth Kübler-Ross in Tuesdays with Morrie (at the Colonial Theatre through October 30), the stage adaptation by Mitch Albom and Jeffrey Hatcher of Albom’s bestselling 1997 account of his weekly meetings with his beloved (if long neglected) former Brandeis sociology professor, Morrie Schwartz, as the latter was dying of Lou Gehrig’s Disease. The play is jokier though no less aphorism-laden than the popular volume recounting the workaholic journalist’s reunion with his favorite teacher, with whom he proceeded to audit a last class on "The Meaning of Life" and learn to smell the roses.

Brandeis fixture Schwartz would appear to have been a wise as well as a mischievous man. And both his painful diminishment and his joie de vivre are adroitly communicated by 81-year-old Harold Gould, whose Morrie struggles agonizingly to get a fork into some egg salad but can issue a merry "Gotcha" from his deathbed. Dominic Fumusa has the harder job, since there is way too much Mitch in Morrie for the character not to seem opportunistic. Fumusa’s performance is affable but stiff — though that may be the idea, as Schwartz is determined to "loosen up" his student as well as use him as conduit for a simple, adamant philosophy rooted in Auden’s contention that "we must love one another or die." People inspired by the fortune cookie of a tome will also be inspired by the play; I found its mixture of maudlin sentiment and shtick a little jarring. It’s as if the production, which is directed by Michael Montel, were afraid of the somber urgency of Morrie’s life embrace. How about Tuesdays with Beckett?

As trim as Beckett but eerily reminiscent of early Pinter is British playwright Caryl Churchill’s 2002 A Number, in its Boston premiere at the Lyric Stage Company of Boston (through November 19). The Pinter connection is particularly striking in Spiro Veloudos’s production, where the spare, elliptical, oft-truncated dialogue retains its English accent — which actors Steve McConnell and Lewis D. Wheeler can handle and which allows Wheeler, who plays three characters, to distinguish them by class, a subject that, even when it’s not the subject, matters to Churchill.

The subject of A Number is human cloning and how it might affect individual identity and self-worth. At the outset, an adult son confronts his father with his discovery that he’s a clone — not just a secret twin but one of "a number" of men whose genetic make-up is identical. Salter, the father, is by turns shocked, evasive, and revved for legal action. Unauthorized medical experimentation, he reckons, may have damaged his son’s uniqueness and "stolen" his identity, and there must be remuneration. Salter assures son Bernard that he is the original, the others copies. But as the play evolves, turning into a controlled-nightmare variation on My Three Sons, it becomes clear that the older man and candor are reluctant bedfellows.

What’s spellbinding in A Number is the way Churchill melds imagined possibility with almost clinical terseness. Eugene Lee’s set for the 2004 New York production, which starred Sam Shepard, turned the theater into a 19th-century operating theater. At the Lyric, set designer Skip Curtiss backs the arena with what looks like something subtly shifting under a microscope. The play is both a cryptic exploration of the nature/nurture debate and an archetypal father-son confrontation played out in duplicate. Two of the genetically identical characters have a history with Salter, who it turns out went to some lengths to get a second chance at parenthood. The results are a formerly benign offspring, now cut to the quick by the discovery he’s one of a "batch," and his menacing, sociopathic predecessor. Even more frightening, however, is the stranger Salter meets at the end, an affable, empty-headed, apparently untroubled exemplar of normality who must apologize to his wounded, unintentional progenitor for liking his life.

McConnell might be edgier as Salter, but he conveys the pain of affections alienated and guilt sequestered as long-time rationalizations crumble. And Wheeler does excellent work, especially as the threatening, linguistically exacting blast from the past — who makes it quite clear a child is not something that, like a sketch on paper, can be crumpled up and begun again. A Number lasts only 65 minutes, but if you factor in the time you spend thinking about it, it’s not that short.