Let’s face it: Family, sanctified by our society (and most others) as the holy of holies, is well‑known to be the root of neuroses, bad habits, identity confusion, frustration and melancholy.

But when you have as big a heart as Billy Crystal, it can also be the source of expansive good humor, enormous understanding, and raucous, unrelenting belly laughs.

“700 Sundays,” a one‑man play written by and featuring Crystal, is the actor/comedian’s autobiographical homage to his birth family. Playing through this Saturday at Gammage Auditorium in Tempe (www.asugammage.com), it is the funniest thing you’ll ever see on a stage short of Charlie Chaplin’s reincarnation. With some comedy you laugh until you cry. With Crystal’s deadpan honesty nailing every foible of human existence, and ruthlessly roasting every flaw in those around him, you’ll laugh until you want to yell, “Stop already!” Real comedy is more than a little cruel. Yet somehow, we forgive it.

The title comes from the fact that Crystal knew only 15 years–about 700 Sundays–his father, a loving and generous and somewhat sad man, someone whose own greatness was generally unacknowledged until this show. Billy Crystal’s dad was one of the great nurturers of jazz in the 1950s, the owner of Commodore Records, and a true champion of that all‑American art form. Young Billy grew up with jazz greats jamming in his house and talking about life. One of them–we won’t give away which one–even took him to see his first movie. As it turned out, that movie was “Shane,” featuring none other than Jack Palance, whose leathery cowboy presence would one day lend stirring dimension to Crystal’s film, “City Slickers.”

Throughout the show–nearly three hours (including intermission) that roll by with the ease of reuniting with an old friend–we are reminded by a variety of references to his career that Crystal isn’t Everyman; he’s a star, a celebrity. And the truth is, “700 Sundays” wouldn’t work if he weren’t. We wouldn’t care nearly as much about Crystal’s life, because we wouldn’t know him.

That’s the strange thing about celebrity in the modern sense: It doesn’t lift the person into a distant place like a god; it makes him uncannily familiar. Politicians aren’t celebrities, because they’re too far above us (or seem to be). But even while movie stars and rock stars may in fact have much more money and even more power than many politicians, they aren’t above us. They are us–sometimes more than we are. I’ve chatted amiably with Frank Zappa and Alice Cooper. I’ve stared into the eyes of Sen. Jon Kyl and not known what the hell to say.

Crystal may be the only comedian who so perfectly balances intellectual with physical humor. He can take us into a mental space where concepts and images collide like quarks in a nuclear accelerator, or he can simply show us how an uncle looked like a Great Dane from behind. Sometimes he combines the two, as in the uproarious description/depiction of his experience as a 5‑foot, 7‑inch guard in a varsity basketball game.

The star of “When Harry Met Sally” and “Analyze This” does an excellent job of summarizing the life of a Boomer. We’ve all been there: the Kennedy assassination, the Beatles, the ‘60s, the growing up when you never thought it would be necessary. Much more than that, though, Crystal bends his celebrity into a prism to capture what it means to be human; to make big mistakes you can never correct; to regret and  regret you’ve regretted; to move forward, anyway.

And did I mention he’s funny?