In 1973, the Mexican cabaret-parody El Grande de Coca Cola made its premiere off-Broadway, and it has been a micro-cult sensation ever since, proving itself and its comedy to be irrepressible, with productions cropping up all over the country. The latest rendition of the show, originally written and performed by Ron House, Diz White, Alan Shearman and John Neville-Andrews, is at Santa Monica's Ruskin Group Theatre, with Shearman serving as the show's director and musical director and House returning in his original role as the dreadful cabaret's grinning, ingratiating emcee, Pepe Hernandez.

In 1974 in L.A., a year after El Grande de Coca Cola premiered in New York, Gary Austin set up shop for the Groundlings in the 30-seat basement of the Oxford Theater (later home to the Los Angeles Theatre Center and currently the MET Theatre); the troupe relocated to its current digs on Melrose Avenue five years later. Actors in the sketch comedy troupe have been poached by TV comedy shows ever since, Saturday Night Live in particular. The Groundlings now is the grand-daddy institution of local improv and sketch comedy, even if it hasn't kept pace with the edgier offerings delivered by Upright Citizens Brigade, the Clubhouse and the Steve Allen Theatre. The company's latest offering, Groundlings Online University, opened last week. (Like most Groundlings shows, the title has nothing to do with the content.)

Both of these comedies include smatterings of improvisation but mostly, they are an homage to vaudeville.

Austin may have imagined that he was incorporating a technique for creating improvisations onstage, inspired by Viola Spolin — the now-legendary American acting teacher who urged thespians to improvise in rehearsals in order to make their scenes more truthful. Yet the cumulative result of Groundlings shows, including the three of four brief interludes of improvisation amidst 18 or so skits, derives from Borscht Belt humor: microcosmic sex farces and freak shows that take stereotypes, make them 10 times larger and more grotesque than they already are, upend them and then put them back again.

The result is their persistent and enticingly ribald mockery of the disabled, the infirm, the stupid, the sexually perverted and those cast out and asunder — precisely the brand of cruelty we're told we should rise above if we're to call ourselves civilized. When they're at their best, the Groundlings' shows bring out our worst — while we're clutching our guts in laughter. It's an odd phenomenon and an enduringly popular one, made more trenchant by the company's determination to keep pop culture references current. This certainly would explain the waiting line of 20-year-olds around the block for the 10 p.m. Saturday night show.

El Grande does much the same but without the contemporary references — despite the efforts of the co-creators to update the show. The audience at the performance I attended was of mixed ages, and the humor clearly was resonating far more deeply with the older patrons than the younger ones.

There's live transitional and accompanying music in each, keeping the energy flowing, since you can't find a plot in either.

Groundlings Online University, directed by company veteran Karen Maruyama, contains a couple of sketches that are emblematic of the Groundlings formula. Alex Staggs' “Dream Self” depicts an exhausted married couple tumbling into bed together and wishing each other well for the night. The sheets have a kind of zebra stripe pattern, beneath which the man (Staggs) and woman (Annie Sertich) disappear with an oh-so-familiar “G-night, babe,” before Staggs starts emitting something between a snore and a vaguely sexual squeal. Naturally Sertich rolls over, “Honey, honey, you're snoring funny.” “What do you mean snoring funny? I'm sorry.” He adjusts his position. They settle in, and the squeal-snore resumes. The way Sertich's face re-emerges from the sheets is straight out of I Love Lucy.

The build of comedic tension is classic. She finally has to wake him once again, to explain that his snores sound like “an Asian hooker.” OK, now we're deep into un-PC turf. I can't reveal how they extract themselves from their plight. The resolution is too easy, but the addictive joy lies in those grotesque comic builds, which recur in scene after scene.

Greg Worswick's “Ri Ri” concerns a preteen misfit (Worswick) and the babysitter (Matt Cook) employed to supervise him while his single mom (Sertich) has a rare night on the town. You can tell before it starts that this is going to be a hostage sketch, and that the babysitter will be the victim.

The only thing the kid — who emphasizes that he has no father and therefore should have his desires met — wants to do is listen to Rihanna, which the babysitter tries to tolerate. The kid lip-syncs to each song, moving with increasingly sexual gyrations while the babysitter watches, ever more flustered. The wit lies entirely in the escalating, ancient comedic blend of grotesquerie and absurdity. Even when the scenes don't pay off, there isn't a single one that doesn't contain such flickers of delight.

Sertich returns in her own “Pick Up the Sign,” an extended excuse for her to play a mom performing for her son and his friends, lip-syncing and dancing with rising, unrepentant flamboyance to a Michael Jackson song, while interpreting the lyrics in sign language.

El Grande, set in Trujillo, Mexico, is performed almost entirely in Spanish, though no worries for non-Spanish speakers, since the physical comedy is too broad and the dialogue too peppered with English-isms for the meaning or the humor to be lost. It's a classic setup: The headliners for the cabaret have checked out for the night, meaning that the ragtag team of remaining thespians, magicians, musicians and dancers have to pull the show out of the hat. They do this with what might be called aggressive mediocrity, which impresario/emcee Pepe Hernandez (Ron House) covers with bursts of forced laughter, rolling “r”s in his speech that try to cover disaster with flourish, and a perpetual, unwitting expression of terror. Pepe is joined by his two saucy daughters, Maria and Consuelo (the marvelous Nina Brissey and Lila Dupree).

There's a blind blues singer who falls off the stage, a pair of nose-in-the-air, prancing queens (all of these cameos are played and sometimes overplayed by David Lago and Aaron Jackson) and a very funny daredevil act in which a marksman attempts to shoot a bullet through a balloon, to soften its trajectory, so it lands gently in the mouth of Pepe's very apprehensive daughter. To make things more dramatic, the marksman shoots while looking in the opposite direction through a mirror.

On the way home, I stopped off to grab a taco from a street vendor. A blind, homeless guy bumped into me and then crashed into and knocked over a garbage can, sending its contents spewing out onto Vine Street. He then fled, cane in hand, into the recesses of a parking lot. Nobody around laughed.

But when “blind Joe Jackson” fell off the stage in El Grande, everybody laughed.

This has little to do with what's “appropriate” and what's vulgar — it has to do with the way vaudeville reframes human pathos as a cartoon, with ancient forms of humor that release demons lurking within us in waves of mirth. However perverse that may be, it's as old as the hills.

EL GRANDE DE COCA COLA | By Ron House, Diz White, Alan Shearman and John Neville-Andrews | Ruskin Group Theatre, 3000 Airport Ave., Santa Monica | Fri.-Sat., 8 p.m.; Sun., 2 p.m.; runs through Sept. 28 (no perf Sept. 1) | (310) 397-3244 |

GROUNDLINGS ONLINE UNIVERSITY | Written and performed by the Groundlings | Groundlings Theatre, 7303 Melrose Ave., W. Hlywd. | Fri., 8 p.m.; Sat., 8 & 10 p.m.; runs indefinitely | (323) 934-4747 |

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