No, the Comet isn't hosting an Alcoholics Anonymous meeting during the Capitol Hill Block Party (though maybe they should). Rather, they're throwing their own adjoining party with NYC noise-jammers Aa (pronounced "big a, little a"). Aa are three guys on percussion and one on samplers and synthesizers, making a rhythmic racket. Their aerobic live shows are part sweat-soaked vision quest, part ritual dance. With Das Llamas and the Pleasureboaters. (Comet, 922 E Pike St, 323-9853. 11 pm, $5, 21+.)