There are encores, and then there are encores. The King's Singers' last offering to a warmly appreciative audience at the Kennedy Center last night was a swinging arrangement of "Deck the Halls" that included a flourish of kazoos and a good-natured poke at energetic, slightly tipsy sing-alongs -- complete with a nicely cued hiccup after the laughter died down.

The Singers' program ranged from serious to silly, and sparkled throughout. Perhaps the widest-ranging piece was John Rutter's musical setting of Kenneth Grahame's "The Reluctant Dragon," in which David Grant's text was narrated by Robert Aubry Davis. Rutter's delightful hodgepodge -- from classical to scat singing -- was tailor-made to showcase their versatility.

That ability to bridge styles was clear through much of the concert. Some of the songs had a touch of fire that bordered on jazz. This was never excessive; the classic "Stille Nacht" was stunning. Jeremy Jackman's clear, powerful countertenor transformed the concert hall in "Virgen sancta," one of several exquisitely performed pieces of Renaissance-era music. The voices were finely blended, the diction flawless, and the dynamic range impressive throughout. A swinging refinement glowed through the sprightly "Noel, Noel."

The National Symphony Orchestra, conducted by Fabio Mechetti, gave unobtrusive accompaniment through much of the program and played some seasonal chestnuts -- selections from "The Nutcracker" and Vaughan Williams' fantasia on "Greensleeves."

The performance will be repeated tomorrow.