The final concert of the Arlington Symphony's "Discovery Season" Sunday was itself full of pleasing discoveries. Among the surprises were the performance space, the Ballston Commons, and the symphony, which proved to be an excellent pops orchestra.

A wide variety of local performers graced the makeshift stage in the cavernous Commons for a program billed as the "Ballston Pops." From the first few lilting bars of Johann Strauss' "Blue Danube" echoing out of the atrium, it was clear that music director David Sz. Pollitt had constructed an evening of music that would exploit the peculiar acoustics of the space.

Audience members enjoyed light fare at flower-bedecked tables on the orchestra level and two floors above, peering down over the orchestra.

The symphony established its pops credentials in the first set of waltzes and marches, including Franz Von Suppe's "Overture to Poet and Peasant." In the "Overture," principal cellist Brigitta Czernik-Gruenther's sensitive cello solo gave way to a joyfully explosive reading by the full orchestra.

The set concluded with master of ceremonies Ralph Black, of the American Symphony Orchestra League, imploring Pollitt to pay a "spontaneous" tribute to Flag Day. Pollitt complied with a rousing rendition of "Stars and Stripes Forever."

The symphony later launched into the rondo section of Carl Maria von Weber's Clarinet Concerto No. 1. Arlington Symphony clarinetist Rick Gibson's gently rolling performance was impressive in its own right, but also a testament to the development of an orchestra capable of drawing such talent from its ranks.

Soprano Annie Newstead, 14, bounded onstage for an energetic performance of "Tomorrow" from the musical "Annie." The young singer became a quick-change artist when she threw off her red wig and put on a white dress for the next number, "Over the Rainbow," from "The Wizard of Oz."

Baritone Charles Williams and soprano Rosa Lamoreaux gave a glamorous, show-biz quality to the final third of the concert in songs primarily from Broadway musicals. Their voices blended nicely as did their theatrical gestures, particularly when they danced across the stage at the conclusion of "Shall We Dance."

The audience was treated to a final discovery when Pollitt, originally trained in violin, traded the baton for the bow with concertmaster Louis Wolcott.