As Gil Shaham wandered through the back offices of the Hirshhorn Museum and Sculpture Garden in Washington, D.C., he said he felt "like Ben Stiller in Night at the Museum." For this impromptu Bach mini-recital, the violin superstar momentarily became part of the art, bathed in the modish lighting and projections of a multimedia installation during the performance. A crowd packed the exhibit room to watch as Shaham launched into Bach's third partita. After the performance, the violinist greeted fans in the museum, many of whom were headed to his concert at the Kennedy Center that night. He seemed surprised and delighted that the guerrilla concert, announced only on local classical station WETA and Twitter that day, drew so many people willing to hear Bach in the afternoon.