Like a lot of theater artists, I don't trust shows that are commercially successful. When I see "Now in Its 18th Hilarious Year!" plastered over a poster, I assume this is due to an impervious blandness, like an aged jar of peanut butter—you might not die if you eat it, but you probably won't enjoy yourself. But I am also awfully curious as to how they do it. How do shows like Defending the Caveman—which visited the Kirkland Performance Center last week (don't worry, it'll be back again in May)—and Late Night Catechism, which this month celebrates its 10th anniversary in Seattle, not just survive but go from success to success? What kind of success? In the case of Caveman, which originally visited Seattle back in 1997, we're talking about a show that still holds the record for the longest run of a solo show on Broadway, and currently has 15 separate dates this month across the country as well as an ongoing Vegas production, with no less than eight separate Cavemen performing hither and yon. (The original writer-director, Rob Becker, retired from the gig back in 2004, after performing the show for nearly 20 years.) It's also got recurring tours in 20 other countries—you haven't really experienced the show, apparently, until you've seen it in Estonian. As for Catechism (which has been housed at ACT for years), it's had extended engagements in Chicago, Florida, New York, and just about every other theater city in America, and spawned two sequels, including a Christmas version that uses a full choir. Both shows don't look like much on paper. As Seattle's nun, Aubrey Manning, observes of Catechism: "The script's only 30 pages long. Most of it's interaction with the audience. My director told me when I started that you're just half of the cast; the rest of them show up late and don't know their lines." Isaac Lamb, the "West Coast Caveman" who's been playing the show for four years, admits he "didn't really see the humor" in the script. It was only after seeing how audiences reacted to the material that he saw how to make it work, a process that still mystifies him a bit, as he's only 27 and unmarried. "I relate a lot of what I'm talking about to my parents, not myself. But our audiences, particularly couples, relate to every joke and every point. They do most of the work." I've seen both shows (in fact, I've seen Catechism three times). Neither knocks your socks off—Becker's monologue is a humorous assessment of how men and women misunderstand each other, and Catechism's nun is more a quirky philosopher in a habit than Nunzilla. She remains more interested in sparking dialogue than arguments ("I'm not Don Rickles in a habit"), and the show's a gentle way to experience some interactive theater, even on "Drunk Catholic Schoolgirl Fridays," as Manning refers to the evenings with bridal shower parties in attendance. Neither show is particularly relevant to current society or politics, but relationships and religion are slow to change. Becker's show predated the Men Are From Mars relationship books of the '90s, and its very thesis hits a number of basic truths—men enjoy hunting, women enjoy gathering; men seek solitude for thinking, women seek other women. These thoughts aren't revelatory, but Lamb also believes that since marriage is such a weighty issue for couples, the show gives them a chance to laugh and release some of that tension, theater as couples counseling. Humbling as it is to admit, a wise-cracking nun and a guy who talks about how he hates shopping with his wife turn out to engage more people than not only most experimental theater, but most mainstream and commercial theater as well. During Catechism's run, ACT has tried out a half-dozen different pocket musicals or other crowd-pleasers that have frankly failed to please. So what's their secret? I'm afraid it's simply that they do what so much other theater fails to do: entertain, engage an audience, and stimulate conversation.