For diehard fans of the blues, there’s only one show worth flocking to this afternoon: the two-day music festival CHICKEN RAID 2008. Eddie Kirkland and Roy Lee Johnson headline, with featured performers including the Fat City Wildcats, Bill Sheffield, Sean Costello and Mudcat. The event honors the late country blues giant Frank Edwards; a part of the proceeds goes to the medical expenses of trombonist Lil Joe Burton. 3 p.m. Saturday, March 22 and Sunday, March 23 at Northside Tavern. Admission is $15. www.myspace.com/thechickenraid.