For more than two decades, bassist Bubba Hernandez and the rest of the band Brave Combo forged their own, shall we say, unique identity in the realm of world music. Blending polka with the rocking flavorings of its rural Texas upbringing, Brave Combo toured the world, won two Grammys, and appeared on The Simpsons. In the last several years Hernandez has launched multiple side projects, including Polka Freak Out, which teams him with accordion virtuoso Alex Meixner, a master of Austrian/Slovenian/Eastern European styles. Together they mix traditional European polka with Tejano and Conjunto rhythms, producing a wacky, danceable pop-rock sound. Bubba Hernandez and Polka Freak Out play Milestones Music Room, 170 East Avenue, 325-6490, on Saturday, December 9, at 7 p.m., $10 advance, $12 day of, 18+.