WHYY (Channel 12) brings it back tonight, devoting the entire evening to back-to-back airings of Weirdly Cool, the Firesign Theatre's first TV special, primarily material performed in late summer before a small Los Angeles audience packed with balding beard-o's.

As I watched the tape, more than 30 years out of college, sober as a TV critic, bearded but not balding (thank goodness), I laughed again at the Firesigns and their timeless creations - Antelope Freeway, old Same place, former celebrity George Tirebiter, and all.

The four men in the comedy troupe met when they were working in the counterculture FM radio of the '60s. Their humor is frenetic and relentless, crammed to overflowing with verbiage. Their live performances include some physical shenanigans, but the comedy remains 99 percent auditory.

Like a James Taylor concert, Weirdly Cool is a perfect nostalgia grab for a PBS fund-raising show, aimed squarely at the liberal baby-boomer audience that devours National Public Radio and is inclined toward, but not addicted to, public television.

Like the transvestites-for-a-night who have been turning up weekly at showings of The Rocky Horror Picture Show for years, hard-core Firesign fans can recite, with relish, every line of the old-time bits.

But the troupe had a much smaller audience than Taylor did. Will newcomers enjoy the dense interplay of the four loons whose grabs for laughs reach all the way from the immediacy of sophomoric puns to the faraway hills of socio-political-historical criticism?

The show is designed to lure newbies. At the top, big stars extol the Firesign comedy.

"The audio equivalent of an Hieronymus Bosch painting" - Robin Williams.

"A treasure of cultural commentary" - George Carlin.

And then we are introduced to that irresistible automotive legend, Ralph Spoilsport, in his red-white-and-blue top hat and tie - and the routine "How Can You Be in Two Places at Once When You're Not Anywhere at All?" is off to the races.

"Hiya, friends, Ralph Spoilsport, Ralph Spoilsport Motors, the world's largest used nude and new glued automobile dealership. Ralph Spoilsport Motors, here in the City of - Emphysemia."

It's as much a classic of comedy as Beethoven's Fifth is of music, and, like a concert pianist, Phil Proctor, who plays Ralph, provides a couple of interpretive moves for this performance.

The rest of the show provides similar riffs on the beloved material. Babe, star of the original "How Can You Be . . .," is transformed into Babe Boomer. One of the signs along the highway reads: "Big Indian Bingo Burial Mound Casino - Give It All Back."

The 90-minute show (including pledge breaks), which begins at 8 and again at 9:30, showcases three Firesign skits and little bits of interstitial material, including an actual TV ad for a Southern California automobile dealer with a sense of humor that they filmed in 1969.

It will also include pledge breaks, some of which will be done live by the comedians, who have been brought to national TV on PBS through the sponsorship of WHYY.

There will be taped pledge breaks, too. Proctor, the putative leader of the troupe, crystallizes the humor and the practicality of the project in sublime Firesign fashion:

"You know, I'm personally a long-time contributor to PBS because I know that it's people like me who make it possible for people like me to be here on television asking people like me to support me."