THE CONCERTMASTER TAKES A BOWThursday and Saturday: Violinist Erin Keefe has been anything but inaudible in her first year as concertmaster of the Minnesota Orchestra. But she hasn't been heard locally as a soloist in a concerto -- until now, that is. Aiming high, she's chosen Beethoven's lone Violin Concerto as her vehicle; we'll know her much better once we've heard her play it. The "Coriolan" Overture and the "Eroica" Symphony flesh out the all-Beethoven program, led by Osmo Vänskä in a relatively rare Sommerfest appearance. (7:30 p.m. Thu., 8 p.m. Sat. $25-$65. Ted Mann Concert Hall, University of Minnesota, 2128 S. 4th St., Mpls. 612-371-5656 or www.minnesotaorchestra.org.)