THEATER REVIEW : INTERNATIONAL THEATRESPORTS : Matching Wits : People in the audience or on stage who offer a bad idea have to wear a paper bag.

More than any other kind of theater, the improvisational variety is dependent on the audience, almost as much as on the actors themselves. That was certainly the case last Saturday night, when Ventura’s chapter of the international TheatreSports organization took on members of the Los Angeles chapter in a couple of hours’ worth of collective--and competitive--ad libbing. The show was the most recent installment in the local group’s regular series of third-Saturday-of-the-month shows at the City Bakery in Ventura.

No matter how quick-witted and talented the performers on stage are, a lazy or slow audience--or a too “creative” one, for that matter--can turn the evening into a disaster.

There was no disaster, particularly, on Saturday. Everybody involved, in fact, seemed to be having a good time. But it’s just as well that nobody seemed to be especially interested in enforcing the rules of the competition.

The announced panel of judges never materialized; instead, the audience was allowed to decide whether the Ventura or L.A. team won.

Perhaps real judges would have more strictly enforced some of TheatreSports’ rules: If the action on stage gets dull, judges equipped with bicycle horns can order the troupe to move on to a new situation, and anybody--on stage or in the audience--who submits a notably bad idea is condemned to wear a paper bag over his or her head.

Neither horns nor bags were put into use on Saturday night, though not for lack of dull moments or dopey ideas.

Representing Ventura in the competition were Russell Seveney, Tom Mueller, Ken Duncan, David Gullett. The Los Angeles team consisted of Sherry Bilsing, Kari Coleman, Brad Sherwood and Dan O’Connor.

The best of the sketches--inspired by audience suggestions--were a quite amusing Polynesian adventure by the Ventura squad in which a virgin sacrifice and slaughter of a sheep were combined into the killing of a virgin sheep (maybe you had to have been there), and Los Angeles TheatreSports’ “four-way-dubbing” sequence, during the course of which each of the four players supplied both his own action and another member’s dialogue. The bit required a good deal of facility and imagination--as well as, one suspects, a good deal of practice.

The improvs were occasionally hampered by some less-than-thrilling audience submissions: After one spectator titled an upcoming bit “Edge of the Abyss,” another could do no better than “The Blue Abyss.” Asked to fill in a piece of dialogue after “I’m going to put my foot down. I’ll have to . . ., “ the best the audience could come up with was “put my foot down” again.

Some of the actors fudged a bit as well. Asked to recreate a Pinteresque drama, a thrown-in reference to the playwright’s “The Homecoming” seemed sufficient to keep him from being bagged.

For the second half of the evening, the two squads joined, with the Ventura team augmented by Sally Mueller (Tom Mueller’s wife) and Christy Bell.

The highlight of the second set was a rap, started by Brad Sherwood, in which several of the players improvised effectively on the audience-suggested subject of “baldness.’

That and a couple more of the group improvs suggested that competition aside, the interaction of skilled performers who had met only hours earlier might well be pursued in the future.