Onstage, the Seabees in South Pacific distract themselves with "volleyball and ping-pong and a lot of fancy games." Off-stage, two of the Seabee actors are less rule-bound in their activities. In their shared dressing room, Eric Anderson and Christian Delcroix, who play Stewpot and the Professor, have constructed a two-man act: E & Croix. (The latter is pronounced "croy," which, appropriately for this pair, rhymes with joy, not the Frenchier "cwah," which means cross and suggests a burden to be borne, which the Professor definitely ain't.)

E & Croix appear every Wednesday through Saturday on YouTube, and on their own Facebook fan page, in a running routine called "FIVE TILL CURTAIN." They face the cam on their dressing-room laptop (E is foreground, Croix in the back, acting at times like a little brother who is desperately trying to secure his older sib's attention), and talk and sing and gadabout like a pair of 21st-century clowns. Their display begins promptly at five minutes till eight; initially it was streamed live, but that ended when E realized he could construct funnier bits by enhancing the material during breaks throughout the show - with sound effects, mostly - and posting each episode around midnight. 

In their dressing room the other night, during the countdown to their Comic Countdown, Anderson confessed to me (and "confessed" is the only way to describe the high-spirited online crimes these guys commit) that the original brainwave for FIVE TILL CURTAIN had been his. "We had just gotten fairly reliable Internet connections in our dressing rooms. I wanted to take advantage of that." 

So, on October 7, after a trial run or two to make sure their connections were working, E and Croix launched. The routines are sometimes slightly scripted, but, E remarked, forethought doesn't always work. "No matter how grandiose our ideas, we always end up in a melee," he said. 

"We're big on holiday themes," said Croix. Near Thanksgiving, for example, E hatched a little rap called "Giblets." For Halloween, they pasted on scarily thick mustaches and coaxed fellow cast members into their den for a "Super Mario Halloween Dance Party." Hopping about on camera in "Pee-Wee's Playhouse" fashion were Larissa Romain, Kimber Monroe, Luka Kain and various adults whose names I won't mention lest it permanently mar their careers. I have rarely seen such backstage glee. (Speaking of glee or, rather, "Glee," the next time SP's former Lt. Cable, now television superstar Matthew Morrison, alights backstage for a visit, if he doesn't make a FIVE cameo to help juice the ratings he'll be fitted with cement shoes and depth-charged permanently into the real South Pacific.) 

By now you're probably wondering how two responsible actors -- with Equity cards! - can be performing backstage right up until the stage manager calls "Places" and still make it from their downstairs dressing room up in front of the footlights of the Beaumont. "With the show's beautiful long overture," E commented, "and then the first scene between Nellie and Emile, we don't have to go on until a good half hour after the curtain rises. We couldn't get away with this otherwise." 

Speaking of getting away with things, just how far are the guys willing to go to test the limits of good taste during their broadcast? "I suppose that we do occasionally venture into 'pooh humor,' E said, "but we're careful not to offend anyone - anyone we know, that is." 

Chimes in Croix: "If one of us says something too outrageous, the other one will bat him down, so the audience knows that we've gone too far and we're aware of that." 

The chief method to convey this dressing down, and the signature gesture of FIVE TILL CURTAIN, is the slap. Watching their routines on YouTube, I was reminded of a headline on a review of one of those old movie melodrama showdowns pitting a heavyweight Joan Crawford against some now-forgotten and thoroughly outclassed studio ingénue: "A Real Slapathon." 

The men's slapstick was taken to its limits in a Halloween special called "Slap the Cat" that serves as their Citizen Cane to date. Croix dressed up as a feline and prowled the halls outside the SP dressing rooms, knocking on doors. Each time he announced "Trick or Treat?", he was roundly slapped by a cast member. 

And speaking of cast members, the cinematographer for an episode called "Superstitious Minds" was Andrew Samonsky (Lt. Cable), who displayed a heretofore unseen talent for holding a camera while scuttling backwards. (IsLittle Mermaid touring and is the part of Sebastian the Crab cast yet?) 

The animal overtones and sound effects betray E and Croix's debt to cartoons like Tom and Jerry, but whom do the fellas consider their more human influences? 

"The Three Stooges for sure," E said. "And Laurel & Hardy," Croix adds. "Also Dean Martin and Jerry Lewis," adds E, which explains E's appropriation of a Dino mannerism: calling his partner - and just about anyone who comes too close - "pally." 

Mostly, though, E & Croix have invented their own demented vaudeville, a kind of show within a show, an effervescent demonstration of the lengths to which backstage actors will go to keep themselves agile and give themselves game. As E puts it, "This definitely helps cure cabin fever." 

BRENDAN LEMON is the American theater critic for the Financial Times and the editor of lemonwade.com.