A full and happy house assembled on Sunday for the grand finale of this year's festival, which has hit one high note after another all month long for the Seattle Chamber Music Society. And it's clear that much of the credit for this success goes to artistic director James Ehnes, whose own violin virtuosity is coupled with program-making and public-speaking skills that few could match.

This year, Ehnes has designed the programming so that each of the concerts features a work that has never been performed before in the festival's 29 years — no easy task, given the huge repertoire list assembled over nearly three decades. For the last work in the final 2012 concert, Ehnes picked a Prokofiev rarity, the ballet "Trapeze." Fortunately, he also chose a lineup of artists who expertly plumbed the drama and excitement of this neglected score. Not every obscure work is a winner; "Trapeze" was a triumph.

The evening's hors d'oeuvre was Rachmaninoff's early Piano Trio No. 1 ("Élégiaque"), full of romantic gloom and featuring some particularly subtle playing from violinist Amy Schwartz Moretti (joined by cellist Andrés Díaz and pianist Andrew Armstrong). An early Beethoven Piano Trio (Op. 1, No. 2) showcased the remarkable taste and skill of pianist Anton Nel, a reliably terrific player who knew exactly what to do with the trio's virtuosic requirements. In one passage, he roared up the keyboard at a blistering pace — stopping just for a teasing hairbreadth before hitting that last note. With him all the way (though in less prominent roles) were violinist Emily Daggett Smith and cellist Robert deMaine.

Prefaced by a witty and frequently hilarious introduction by Ehnes, the Prokofiev "Trapeze" proved a marvel of style and technique, with Ehnes joining violist Che-Yen Chen, oboist Nathan Hughes, clarinetist Ricardo Morales and bassist Jordan Anderson for the performance. Challenging in almost every way, this jaunty, acerbic work is colored with unusual combinations of timbres, strong rhythmic pulses, and all sorts of virtuoso flourishes. The wind players have passages of remarkable difficulty; the double bass barges up the scale from the growly low tones to viola territory, and the eight movements are so rhythmically complicated that it must have been extremely tricky to coordinate the ensemble. The five players made it sound easy. It was a performance well worth a recording.

Melinda Bargreen also reviews concerts for 98.1 Classical KING FM. She can be reached at mbargreen@aol.com.