Kay Kay and His Weathered Underground put on one hell of a sprawling, psychedelic carnival show. A dozen or more players pack the stage, surrounding the standard guitars and drums with a host of horns, strings, and backup singers, not to mention the Super 8 projections and the floral arrangements. At the center of all this is Kirk Huffman's casually pretty voice and Kyle O'Quin's deft pop arrangements. Tonight, the band celebrates the new four-sided ww version of their self-titled, self-released debut by performing the record live from beginning to end. (Triple Door, 216 Union St, 838-4333. 7:30 pm, $10, all ages.)