Who would have thought that grown men and women pretending to be monkeys in love and singing Country-Western songs about going bald would become the hottest thing in comedy?

Improvisation, seldom a big draw, has suddenly become huge. Attributing the boost mostly to an ABC comedy show that was launched last summer, several local comedy clubs have noticed increased attendance at improv shows. They also report more interest in improv workshops among amateurs.

“You wanna’ know why? ‘Whose Line is it Anyway,'” said Cynthia Fzigeti, who runs the workshops at Acme Comedy Theatre on La Brea Boulevard, referring to the new ABC show. “Because of ‘Whose Line,’ (improv) has come to the attention of the general populace.”

Acme owner M.D. Sweeney estimates that audience size and revenue from the club’s weekly improv show have jumped 25 to 35 percent in the past six months, and the show now attracts a full house.

“They’re not your typical theater-going crowd, they’re your typical TV-watching crowd,” Sweeney said.

That is, they’re likely to watch “Whose Line is it Anyway?” Based on a long-running British show of the same name, “Whose Line” is hosted by Drew Carey and features four comedians who improvise scenes based on suggestions from Carey and the audience. Comedians have been asked to mime an underwater sportscast, sing to an audience member in the style of a 1980s rock ballad, and act out a scene in which all the dialogue consists of questions.

“Whose Line” shot into the top 20-rated shows during the slow summer months of 1998, and while slipping somewhat it remains one of the network’s best Thursday-night performers in years.

That has spilled onto the local club scene. The Improv now turns away people looking to catch the club’s Thursday-night show when Drew Carey and his “Whose Line” friends do an improv show using the same format as the TV program. (The Improv is otherwise unconnected to “Whose Line,” which is taped at a studio.)

Improv owner Budd Friedman says the buzz created by Carey’s gang has boosted the popularity of another late-night improvised show, usually the last set on Fridays. “Number one, it holds the audience People stay and a lot of people come in just for it.”

Other clubs also are seeing a significant increase in business.

“It’s like a sporting event, anything can happen,” said James Grace, artistic director at the 3-year-old ImprovOlympic West in Hollywood. “I think audience members see the possibilities of it, they see the excitement of it, and they enjoy it.”

The club is enjoying a good deal of new business, with revenues increasing 22 percent over last year. “When we started out here, it was a money-losing venture, and now we’re definitely not. It’s really growing at an increasing rate,” Grace said. “We did a show on Friday and Saturday night. Now we have shows every night but Tuesday, and every night we have at least two shows, sometimes three or four.”

Actors and writers long have taken improv workshops to step up their ad-libbing or story-idea pitching skills, but club owners say more non-Hollywood types are attending. Since Grace’s club opened, it has gone from holding one 18-student workshop to three.

At Bang Improv Studio, a 5-year-old studio focused on longer improvised scenes, more than 100 students are now enrolled in workshops, triple the enrollment of a few years ago.

If the clubs are enjoying the increased business, so are the artists. Four-year-old comedy troupe the Berubians led a relatively obscure existence until the past year, when it received national attention on “Entertainment Tonight.” Artistic director Chris Berube said he’s noted that audiences lately are more willing to play along.

“A couple of years ago, it may have been perceived as a copout. When you say you’re going to make up a scene on the spot, a few years ago it was like, ‘What, are you too lazy to write one?’ ” he said. “Now you actually see audiences looking forward to it. Now people look for it more instead of complete sketch (performances).”

Yet club owners and artistic directors acknowledge that in the fickle comedy business, popularity can wane as quickly as it came. So while it lasts, they’re focusing on bringing in new customers in hopes of boosting the number of loyal fans who’ll come back after something else becomes popular.

“It’s like jazz, there’s always a core audience,” said Acme’s Fzigeti. “Improv is the jazz of the theater.”