How to write a Margaret Cho joke: 1) Pick a really smutty topic, such as fisting or colonics. 2) Divide Roseanne by Janeane Garofalo, subtract Richard Pryor. 3) Acknowledge loyal gay cult following. 4) Repeat punchline three or more times. 5) Hold contorted facial expression for 10 seconds. 6) Wait for applause. Cho's last concert film, I'm The One That I Want, occasionally broke the formula for a few honest and brutally funny observations about her misadventures on network television. But as the title of her dire follow-up suggests, she now has an overripe sense of her own raunchy irreverence. Shot in front of a rabid audience at Seattle's Paramount Theater, Notorious C.H.O. opens with the ultimate concert-film cliché: A five-minute promotional video featuring box-office lines around the block, man-on-the-street interviews with excited fans, and a few words backstage from Cho herself. From there, she takes the stage with a telling joke, plunging headlong into the giant maw of Sept. 11, only to back off with a tepid bit about blowing the rescue workers at Ground Zero. Right away, Cho shows why her talents are more suited to situation comedy than great stand-up: Given the opportunity to engage the culture and get to the heart of a sensitive issueor at least try an offbeat observationshe peels an easy punchline off her self-styled "Slut Pride" persona. Known for her raw, intrepidly frank one-woman shows, Cho has drawn frequent comparisons to Pryor in her willingness to convert her own painful experiences into discomfiting, socially relevant humor. But there's a difference between autobiography and solipsism, not to mention funny and unfunny, and Cho's cartoonish impersonations and lowbrow vagina monologues seem like so much navel-gazing in comparison. Outside of a few asides about racism, homophobia, and self-esteem issues, she runs through a checklist of conversational taboos, including bits on S&M, the G-spot, pornography, drag queens, oral sex, and periods. And her characterization of gay men (hip, fashionable, sassy) versus straight men (dumb, insensitive, sexually inept) rings as predictable and dated as a black man/white man sketch on An Evening At The Improv. At heart, Cho just wants to shatter a few monocles, but with an audience that's well beyond shock, her straight-ahead vulgarity can't find more interesting tributaries through original commentary or wordplay. Despite her healthy fan base, Notorious C.H.O. looks like the dead-end to a limited repertoire.