Leave it to a hand puppet to pose the central existential question in the hysterically inventive musical “Avenue Q.”

“What do you do with a B.A. in English?”

Princeton may be cut from the same cloth as a Jim Henson Muppet; that is, wide-eyed, overeager and bright orange. But he’s not your toddler’s sort of learning companion.

Fresh out of college, he’s moved to New York City to find his purpose in life. Unable to afford an apartment on Avenues A through P, Princeton winds up on the shabbily eclectic Avenue Q with a friendly assortment of puppet people, real people and hairy monsters, all trying to make ends meet.

Running through Sunday at the Orpheum, the Tony-winning Broadway musical — starring a cast of exceptional puppeteers — is the most adult comedy to come to the theater in, perhaps, ever.

The transvestite pole-dancing in “Rent” has nothing on the graphic puppet sex in “Avenue Q.”

And hold that thought.

The original concept by Robert Lopez and Jeff Marx challenges and enlightens any of us who reached adulthood and found that all those utopian lessons learned down on “Sesame Street” didn’t quite cover all the bases. Like potty training, notions of goodness and beauty were drilled into our heads. But they never revealed that as adults we’ll spend a lot of time dealing with broken hearts, empty wallets and what the show’s creators call the “Bad Idea Bears,” a couple of cuddly, evil Care Bears who persuade us to do bad things because, hey, it just feels good.

Princeton fits in well with the other residents. There’s Kate Monster, a furry young woman who dreams of becoming a teacher. There is Rod, a Republican banker puppet who refuses to admit he’s gay and in love with his straight roommate, Nicky.

The good-hearted real people on “Avenue Q” help the puppets work things out, though they hardly have it easy themselves. Brian is a struggling comedian engaged to a Japanese woman who can’t get a job in part because of her thick accent.

Also, there’s Gary Coleman. The former child star of “Diff’rent Strokes.” He’s the superintendent of Avenue Q, representing the misery of adulthood in all its glory and humiliation.

He (played by actress Danielle K. Thomas) cheerily instructs us in the the meaning of the world “Schadenfreude,” that is, the ability to take joy in other people’s failure.

The lesson: while it may suck to be you, knowing that people are worse off can be great for the soul.

Here are some other lessons gleaned from the exuberant, witty musical numbers in “Avenue Q.”

“Everyone is a Little Bit Racist.”

“The Internet Is for Porn.”

And “The More You Love Someone, The More You Want to Kill Him.”

Conceptually, “Avenue Q” is utterly fascinating to watch. The puppeteers, who also voice the parts, are like doppelgängers standing beside their little friends. The puppets and their handlers move and emote as one, even at times when the actual voice is standing offstage and someone else is operating the mouth.

“Avenue Q” is outrageous, physical, ingeniously choreographed theater that turns out to be surprisingly satisfying on an emotional level. In the way puppets give guidance to children, they also can help adults come to terms with their own issues.

After it’s all over, you’ll be less apt to fret over that other big question in life: “How do I get back to college?”

“Avenue Q” continues through Sunday (Oct. 5) at the Orpheum. Shows are 7:30 tonight (Wednesday) and Thursday, 8 p.m. Friday, 2 and 8 p.m. Saturday and 1:30 and 7:30 p.m. Sunday. Call 525-3000 or go to orpheum-memphis.com.

— Christopher Blank: 529-2305