If you have never been to catechism, you might think it is something that involves rote memorization, taxonomies of transgression, maybe getting your knuckles rapped by a ruler-toting nun.  Not so with Denise Fennell’s inspired performance in the latest installment of Sister’s comedic instruction on how to be a good Catholic—even if you are not one.

Written by Maripat Donovan and Marc Silvia, you will enjoy the humor Fennell spins out, from the moment she comes out and complains that this is the worst gig—catechism for bad grown-ups! And right in the middle of her baseball and popsicle-filled summer vacation with the other nuns. 

If you have seen Fennell before (she has been part of the Late Night Catechism series at Stages for roughly a decade), you know she is a marvel not only at the delivery of a punchline, but also at interacting with audiences and improvising with a mental dexterity that is worthy of envy—even if envy is a sin. 

We are lucky that Stages can fly her in from El-Lay to continue this witty series that is not just entertaining, but a humorous reminder of how difficult it is to humorously address moral issues in a chronically offended culture. The writers, as well as the deft Fennell who must constantly interact with the audience, which changes nightly, have achieved something that I find rather miraculous: They can satirize human foibles and even an entire religion without being blasphemous. How do you do that? I have no idea, but they have it down.

In her glasses and gabardine nun’s habit, Sister Marie Christina calls them as she sees them, whether she’s talking about how inappropriate your sleeveless blouse is or how many cocktails you might have been drinking. Her enthusiasm is contagious—everyone was laughing throughout the evening, and part of what is remarkable about this is that audience involvement is always a dicey thing: You never know when someone will be shy or resistant or not willing to go along with the joke. 

But Fennell has the kind of charisma that you wish could be bottled up and sold at Target—not only do you want to go along on her crazy catechism ride, you don’t want to be left off the train. Whether she is talking about key words from the Bible as she quizzes the audience members from the wonderful school-room set, or handing out prizes when her “students” get the answers right, Fennell is a whiz at the snappy comeback and the look of disbelief she has when discussing our moral failings is priceless.

One of my favorite moments was when she made everyone write down on a card what they need to be forgiven for—not only did the audience have some truly hilarious responses, her delivery of them and assessment of them was a pleasure to watch—you never know what Sister is going to come up with, and that is the thrill of watching this kind of show.

Another component worth mentioning is that Steve Martin was right: Comedy, often, isn’t pretty. But what I love about Fennell is she can interact with anyone, and I do mean anyone—whether it is a kid, a teenager, or a senior. How many comedians can do that? It reminds me of Carol Burnett—her comedy was funny to everyone, no matter who you were, and it was something that brought people together in a good way. Kind of like church is supposed to do. But Fennell can make fun of Catholic practices without insulting them, and that in and of itself is a kind of miracle. When she asks someone his or her religion, the audience can answer any denomination, and Fennell is at the ready with a funny retort that makes you laugh without the insulting nature that marks what so often passes for comedy today. 

Bravo to Sister Marie Christina—and thank goodness we will never run out of sins, so she can continue her classes with wayward Catholics and non-Catholics for seasons to come.

Thru Sept. 9. Tickets from $25. Stages Repertory Theatre, 3201 Allen Pkwy. 713-527-0123. More info and tickets at stagestheatre.com.