Subversive-music snobs may thumb their noses at the first Colorado Underground Music Festival, slated to take place this Saturday, September 20, at the Ogden Theatre. After all, how "underground" can it be if it's held at the Ogden, sponsored by a radio station and includes bands already favorably regarded by the local scene? But even if it's not in a secret warehouse and admission isn't invite-only, the "festival" part of the title is guaranteed. Put together by those AM Revolutionaries at Radio 1190 as part of their Local Shakedown series, the lineup is a hodgepodge of notable area acts. Performances of Black, Black Ocean and Against Tomorrow's Sky are reason enough to attend the gala, but throw in Curious Yellow, Porcelain, Bright Channel, Fifth Utility, the Affairs and Doozer, and even the snootiest music elitists will be unable to resist. Now, aren't you glad there's no password or secret handshake needed to get in?