August: Osage County's three-and-a-half-hour heft and its hilariously harrowing plotlines—even its characters don't know whether to laugh or cry—made it stand out from typical recent Broadway fare, and from 2007's other Pulitzer and Tony nominees. It's even more distinctive now that it's on tour. There's been nothing like it on the Bushnell Broadway season ever, and even the Shubert in New Haven with its legacy of pre-Broadway try-outs of cutting-edge modern dramas in the 1930s-60s would be hardpressed to top a booking like this.

The feel-good-bad tragicomedy sensation of the 21st century, A:OC more than holds its own in the large main auditorium of the lush Bushnell. The show brings its own timing and pacing with it, and seems able to settle in anywhere—anywhere that can handle a 13-strong cast and a three-storey lived-in house-sized set-piece, that is. The national tour may be the last chance to see August: Osage County with Todd Rosenthal's imposing scenic design, which reminds me of similar cut-away full-house effects from the films Absolute Beginnners and Jerry Lewis' The Ladies' Man.

I know this is one of the biggest deal dramas of the past few years, and I know I'm remiss in not seeing it until now. I've read it, but you realize that you lose a lot that way; there's a craziness to the whole enterprise that seems unpredictable, and which certainly can't be accessed in print. I've seen several plays which were clearly heavily influenced by August: Osage County (or share its zeitgeist), but none of those hold a candle to Tracy Lett's extravagantly evil and enraged tale of large-family life in contemporary Oklahoma. There are stereotypes galore, but Letts is an equal-opportunity offender. Lesbians, poets, alcoholics, children, perverts, pill-poppers, officers of the law, New Yorkers, Floridians, teachers, writers, Native Americans and Baby Boomers all get their share of abuse.

What makes it so good? Well, I can't quite tell you without spoiling it all for you, plotwise, so I won't. (I was equally evasive, perhaps too much so, in a preview article that ran in the Advocate last week.) This is a soap-operatic melodrama which pushes past most of the formal conventions of that medium, foments a bizarre over-the-top realism, and helps you laugh at the trying relationships in your own life because those problems are probably puny compared to those on view here. Words like deceit, self-absorption and lust don't begin to do these characters justice. There's more sleaze and fury onstage here than at a WWE stadium tour.

The show doesn't try to be a metaphor about something bigger—government, or modern life—or otherwise try to justify its epic length or its 13-person cast or its monstrous full-house set by tossing in oversized themes. It's big enough already, and its ultimate goals are more modest. It essentially says that we all want very much to find true love, but some of us don't try very hard at all, and probably don't deserve it anyway. If much of this comes off like misanthropic Sartre, it's thankfully mostly entertaiment-minded Chekhov.

Yes, the cast has to strut and shout more grandly than they really should, but at the same time this is a play that builds to huge, cathartic bursts of laughter, to the point where, by the third act, the mere mention of familial discomfort gets a showstopping full-auditorium guffaw. Such a litany and sins and screw-ups have already been accounted for that even an oblique reference to them is a knee-slapper.

This is one of those plays that deserves its breadth and breathing room. It demands a lot of its actors, since to drag the script fully into either either of the directions it pulls you—Long Day's Journey Into Night or Farrelly Brothers triple-feature—would be laughable in the worst way. This cast—invidually strong through not the most fluid ensemble—milk the true laughs but also the true pathos. Sometimes they're overwhelmed—Estelle Parsons, as the matriarch of this embattling clan, seems like she's gone back in time between the play's first and second scene, when she suddenly looks younger and fresher than she possibly could even days after scene one.

Nitpicking actually comes easy—some awkwardly staged moments, a couple of weak links in the cast, an ending that many might consider a cop-out— but it's fruitless. You're either whisked along or you're not, and if you're not, you can always snuggle in a corner with a good book, like the winsome Native American maid Johnna Montevata (DeLanna Studi), the one relatively sane person in this mindbogglingly bleak yet boisterous monstrosity.

August: Osage County continues through Nov. 22 at the Bushnell, 166 Capitol Ave., Hartford. (860) 987-5900, www.bushnell.org