When you put two outspoken lesbian spoken-word performance artists on the same billing, it's no surprise if they make memorable sparks. When it's veteran performers Alix Olson and Kimberly Dark, you can add funny, poignant, acerbic and occasionally downright caustic to that list. Olson and Dark have carved out meaty careers in the spoken-word-slash-poetry world, but they've never actually shared the same stage until Tuesday night at California State University Summer Arts. Alternating their sets, they pumped up the audience with politically provocative fare that had a particular emphasis on queer and gender issues.

Dark (pictured) is a terrific presence on stage: her voice warm, her eyes lively, the physical choices she makes in terms of relationship of her body to the audience somehow reassuring and even nurturing. Yet she's also able to forge a slightly adversarial union with her listeners as well. In her opening piece, a commentary on the tendency for women to obsess about body image and weight, she challenged not only men -- for gawking natures and unrealistic expectations -- but women as well who conform to those male expectations. Dark is a strong writer, each phrase solid and calculated, and her ability to create word pictures is extraordinary. I won't soon forget the image of a woman with scalpel in hand, literally chiseling off layers of fat as if she's some sculptor working in soft stone.

Dark alternated the performance with Olson, who bounded onto stage clad in a "No Divorce for Straights" T-shirt and exhibiting a slightly snarky delivery (with lots of half-muttered asides) and the kind of youthful, zesty energy that you associate with college days. (She makes frequent appearances on university campuses, which can stir a bit of controversy if she manages to slip under the radar and get a gig at a disapproving religiously affiliated institution.) Olson fired off a series of politically edgy pieces that included a notable "breakup poem" with America. In a memorable tribute to women activists who came before her, she invoked notable names as if they were percussive elements. "I take my legacy seriously," she said.

Olson did go on one piece too long in her extended first set, I think, and there was a slightly dated feel to some of her material. (Poking at Wal-Mart commercialism and Vermont-Massachusetts gay-marriage equity gave more of a first-term-G-W-Bush feel to the proceedings than the second.) Also, while both women provided a strong female and queer point of view, it would have been nice if the evening hadn't felt quite so lily white -- perhaps with a stronger nod to the incredible ethnic diversity of this nation's underprivileged classes.

My favorite part of the performance came with Dark's last piece, a touching meditation she wrote a couple of years ago on the upcoming 16th birthday of Dark's son, whom she used to take as a baby to political demonstrations. After the piece, she revealed that her son, Caleb Westberg, was in the audience as a student at Summer Arts, and that he turns 18 on Wednesday. It was a special moment, and one that reminded us that art and real life really do mix.