Chuck Berry is usually content to just go through the motions these days–even his potentially explosive reunion with Matt “Guitar” Murphy and pianist Lafayette Leake at the Chicago Blues Festival a few years ago went flat, redeemed only when Keith Richards showed up and proceeded to blow Berry completely off the stage. But if anything can galvanize him it’s a gig like this one with pianist Johnnie Johnson. Johnson played as big as role as anyone in defining rock and roll piano. He toured consistently with Berry in the mid-50s, and his keyboard-fracturing accompaniment was featured on some of Berry’s most important hits (“Brown-Eyed Handsome Man,” “Roll Over Beethoven,” “School Days”). Recommending a Chuck Berry show is always a risky venture, but the opportunity to see these two trailblazers together is too good to miss–and there’s always a chance the spark will ignite. Tonight, 7:30 and 10 PM, Cubby Bear, 1059 W. Addison; 327-1662 or 477-7469.