Not all Mississippi blues musicians migrated north to Chicago: R.L. Burnside has been banging out raw, rhythmic blues with a touch of soul at his hole-in-the-wall juke joint outside Holly Springs for a number of years. Burnside, whose Too Bad Jim turned up on a number of best-of lists last year, opens for the punked-up rockabilly and R&B of the Jon Spencer Blues Explosion at 8:45 p.m. at the 9:30 Club, 930 F St. NW. $12. (202) 393-0930. (Steve Kiviat)