“It’s on,” funnyman Jeb Berrier was saying Thursday, just a few hours before Telluride Comedy Festival was due to kick off on the Sheridan Opera House stage, almost biting into the receiver of the cell phone that’s clamped to his ear.

“Hold on. It’s off,” he says, finally clicking off the piece of plastic clamped to his ear 24/7 in days leading up to the festival featuring luminaries from the world of American comedy, like Rob Corddry, Ed Helms, Rob Riggle, Brian Huskey, Jessica Chaffin, Jamie Denbo, Bob Dubac, Will Franken, Jason Mantzoukas, A.D. Miles and Seth Morris.

Berrier sits down in a chair and takes off his hat; brown hair on either side of his bald spot frizzes out over his ears, like a clown’s.

This marks the fourth year that Berrier has shepherded friends and acquaintances from the rarified world of comedy in and around Telluride over President’s Weekend for a five-day comedy fest that kicked off last night, like it always does, with Locals’ Night, featuring $20 tickets and no shortage of talent onstage.

Berrier had just come from ferrying fellow Upright Citizens Brigade veterans Morris, Franken and Mantzoukas to the condo they’ll share for four days, skiing by day, improvising by night, no one more attuned to the spinning of delicate threads into side-splitting humor.

The Brigade veterans’ first ensemble performance will be “No Posers,” where they play an indie rock band displaying its creative process for the audience, in a kind of Nirvana meets This Is Spinal Tap, “which should,” Berrier grins wolfishly, “be very funny.”

Friday night features sketches – Berrier, who comes from the Boston area, says he’s especially looking forward to “Kosher Comedy” from Denbo and Chaffin, straight from the suburbs of Boston.

Saturday’s Night of Stand-up will feature Helms, Miles and Corddry; Sunday night brings A Night of Improv, with Corddry once again, and The Naked Babies.

Berrier, famous in Telluride for his star turns in a dilapidated baby carriage wearing nothing more than a diaper, loves nothing more than improv, so much so that he gets downright serious whenever he’s talking about it.

The first rule of improv, he says, is “don’t miss a trick – don’t ignore anything that happens in a scene.”

In a setting as intimate as the 250-seat Opera House, he explains, “the audience sees everything, so any small detail you notice. If you use it, it’s like gold.”

He gives an example: “You’re talking about a scene in a friend’s home life, and you mention his wife.

“Five scenes later, you might see the wife.” The audience is right there with you, he says, “and it makes for a more artful, more complex type of improv.”

Good comedians have “a quick filter” during improv – something Seinfeld star Michael Richard was in short supply of during his unfortunate New York performance that left him lost deep in a racist rant, Berrier says.

Improv, he adds, helps comedians “with their writing; it helps them write bits in a few hours that are hysterical. It’s a skill that gets better as you do it.”

While he’s in a quiet mode, Berrier offers a few insights into what makes for good comedy.

“What these guys tend to have is a very fast, very sharp, very unexpected sense of humor,” he says.

“They tend to stay one step ahead of the audience; I guess it’s about being quick, mentally fast – they’re so good – it’s less about thinking and more about things just coming out, and reacting to them.”

A history of working together is helpful, and most of the comedians Berrier has assembled for the weekend have become regulars at the Opera House over the years.

“They come here, they hang out, they ski – they love it here,” he says of the group he’s assembled. “We get people like them to come back because they love Telluride.”

And like so many performers, they love the intimacy of performing in the Sheridan Opera House.

“When you’re on stage in the Opera House,” Berrier says, “everybody’s just right there,” in an intimate give-and-take setting that ultimately encourages honest give-and-take.

“I don’t think I’d ever want to change that.”