'GREATER TUNA' HAS FRESH, UNCANNED LAUGHS.

Byline: Evan Henerson Theater Critic

THERE'S NOTHING quite like a formula dispensed by the person who concocted the mixture to begin with.

Theaters big and small love ``Greater Tuna'' and its spin-offs. And what's not to love? The two-character play, kind of a demented spin on Garrison Keillor's ``A Prairie Home Companion,'' is a potential comic tour de force as long as you've got the actors, the tone and the wigs to make it sing.

Having never previously sampled a single helping of ``Tuna,'' ``Greater'' or lesser, I have to assume that nobody can pull off this kind of small-town burlesque quite as dexterously as Joe Sears and Jaston Williams, the piece's original writers and performers. Not that they've ever really taken a break, but that same ``Tuna'' duo are at the Wilshire Theatre through Sunday as part of the play's 20th-anniversary tour.

As you watch Sears and Williams open the show as Thurston Wheelis and Arles Struvie, the dry co-hosts of Radio Station OKKK's morning program, you realize that the people who drone about the comfort of old shoes and well-worn jeans know whereof they speak. The patter and overlapped dialogue between these two men is utterly fluid, yet neither actor seems to be coasting. Character after new character saunters out from behind a large armoire-shaped flat, but ``Greater Tuna'' doesn't contain a single rushed moment.

The denizens of Tuna, Texas (the state's third smallest town), include Humane Society activist Petey Fisk, hooligan Stanley Bumiller,his cheerleading-obsessed sister Charlene, used-weapons saleswoman Didi Snavely and perpetual city council candidate Phinas Blye (all played by Williams). Burly Sears takes on Bertha Bumiller (matron of the Bumiller clan), her dog-poisoning aunt Pearl Burras, the Rev. Spikes, R.R. Snavely and, off stage, a dog named Yippy.

GREATER TUNA - Three stars

Where: Wilshire Theatre, 8440 Wilshire Blvd., Beverly Hills.

When: 8 p.m. Friday, 2 and 8 p.m. Saturday, 1 and 6:30 p.m. Sunday.

Tickets: $42 to $52. Call [phone].

In a nutshell: You may be able to recite the jokes, but they're still funny.