Where would holidays be without rituals? This is particularly true of Christmas, where familial variations on certain time-honored themes — the Yule tree, carols, front yard nativity — honor tradition and yet allow folks to imprint the holidays with their own tinsel-draped twists.

Maybe, instead of leaving a cookie and a glass of milk for Santa, you plop Aunt Jeannie's fruitcake down next to the chimney and pray — really pray — the Jolly Old Elf takes the damned thing. Perhaps, rather than attending Christmas Eve Mass, the whole family gathers around the television and watches "Silent Night, Deadly Night." Or, forget chestnuts, you roast a whole holiday elk over the open fire!

One tradition just about everyone can agree on, though, is the Christmas Pops concerts at the Chorus of Westerly. The two sold-out presentations take place Sunday in the organization's George Kent Performance Hall. Conducted by music director Andrew Howell, over 250 singers and performers will present a dynamic selection of traditional seasonal and Christmas carols.

"This is always one of our favorite concerts here," Howell says. "This year we have a program packed full of classic holiday favorites, from 'Sleigh Ride' to 'White Christmas,' as well as some new arrangements of gems like 'The First Noel.'"

And Howell knows of tradition: His 7-year-old daughter, Sadie, takes the stage for her inaugural "Pops" appearance this year — she becomes the first-ever fourth-generation representative in Chorus of Westerly history. Others in the clan are former singer Jane Young, 87, a founding member of the chorus; and still-current vocalists Nancy Young, 58, and Emily Howell, 29.

"I'm so proud and excited to see my daughter on the risers for the obvious, normal parent-y reasons," Howell says. "But the fact that she'll be the first fourth-generation singer to add her voice to the organization is truly remarkable and gives me hope for the many more generations of singers to come."

However, the chorus is capable of other variations-on-a-theme. This includes Craig Courtney's "A Musicological Journey Through the Twelve Days of Christmas" — a work that connects each day within the structure of this beloved song to a different time period in the history of music. For example, the song's kick-off present — the partridge in a pear tree — gets a Gregorian chant treatment. Subsequent "days" receive respective arrangements that span, for example, Renaissance, Baroque, Classical and Romantic styles.

"The 'Musicology Journey' has been in the pops rotation for a while, but we decided to kick it up a notch this year by adding a theatrical element," Howell says.

This is accomplished by a grand processional bisecting the hall that will symbolize the 12 days with special props for the first seven — imagine turtle doves, French hens, gold rings, etc. — and finishing with 50 children costumed to depict days eight through 12.

The staging and conceptualizing of the processional was greatly helped out by Flock Theatre and director Derron Wood. The Chorus of Westerly and Flock have a convivial working relationship — Wood directed the organization's "Celebration of Twelfth Night" productions for many years — and Howell says he knew at once the processional absolutely needed the theater company's input and cooperation.

"Derron's immensely talented, and we called him up to be certain he could be involved," Howell explains. "He has an incredible ability to take a simple procession and turn it into something far more impressive than you thought was possible."

Hey, if you're going to explore the possibilities of Christmas ritual, "far more impressive than you thought was possible" is pretty great — particularly if you're already talking about the Chorus of Westerly's Christmas Pops.

Christmas Pops, the Chorus of Westerly, 4 and 6 p.m. Sunday, George Kent Performance Hall, 119 High St., Westerly; sold out; (401) 596-8663.