Since it premiered off-Broadway in 1982, the two-man comedy "Greater Tuna," which opens at South Park Theatre next Thursday, has remained one of the most-produced plays in the country.

"It's timeless," said director Lynne DeBree, 39, "It could be 50 years ago or today in any small town."

"Tuna" deals with the doings of fictional and deeply conservative Tuna, Texas, residents as broadcast on local radio station OKKK, with all characters played by two actors.

The play grew out of a satiric sketch that playwrights Joe Sears, Jaston Williams and Ed Howard once presented at a party, and Mr. Sears and Mr. Williams still perform the show, with Mr. Howard directing.

South Park's production stars Ron Gmys and Everett Lowe. Ms. DeBree, who returned from her home in Tampa Bay, Fla., to direct "Tuna," said her cast is "fabulous."

"Ninety percent of directing is casting," she said. "I'm spoiled." Ms. DeBree, 39, is a professional photographer.

With 20 characters and 43 costume changes between them, Mr. Gmys and Mr. Lowe both said their multiple parts are challenging, but agreed "Tuna" is a great opportunity for actors. Mr. Gmys, 36, from McKeesport, said he usually acts in only one show a year because of the time commitment it requires. "But I couldn't pass this up."

Mr. Gmys is technical director for Jefferson High School's shows, but audiences may better remember him from his Elizabeth theater company Grand Dream Productions, which he operated during 2004 with wife Stacy Bartlebaugh-Gmys.

Mr. Gmys said his favorite characters to play include DJ Thurston Wheeler, Bertha Bumiller, a member of Tuna's anti-pornography group the Smut Snatchers, and not-so-tolerant minister Reverend Spikes.

Mr. Lowe, 26, an advertising writer from Cranberry, said he enjoys portraying Humane Society member Petey Fisk, churchwoman Vera Carp and used weapons diva Didi Snavely.

Besides the quick costume changes, Mr. Gmys said it was a challenge to avoid making the people of Tuna into total stereotypes. "You need to make it clear who these people are right away," he said, so the audience could recognize them, "but it also has to ring true."

"You start from small details," added Mr. Lowe, "so it feels more authentic." He also said he believes the popularity of "Greater Tuna" works in the actors' favor. "The people who love this play show up ready to have a good time."

"Greater Tuna" at South Park Theatre, Corrigan Drive at Brownsville Road, South Park, plays at 8 p.m. Aug. 16-18, Aug. 22-25, Aug. 29-31 and Sept 1. There are matinees at 2 p.m. Aug. 19, Aug. 26 and Sept. 2. Tickets are $11. Call 412-831-8552.