It's not your grandmother's ugly Christmas sweater anymore.

Those bauble-covered woolen pullovers, long a staple of Yuletide cookie exchanges and family gatherings, have evolved in the last decade into a global phenomenon that has inspired all sorts of creative variations. Now you can not only wear a striped reindeer cable knit or pom pom-embellished Ho! Ho! Ho! sweater, you can also play ugly sweater card games, bake ugly sweater cookies, decorate trees with ugly sweater ornaments, and even buy a matching ugly sweater vest for your dog.

Ugly Christmas sweater cookie kit
Creative variations on the ugly sweater include the Ugly Holiday Sweater Cookie Kit.

"People love wearing costumes, and ugly Christmas sweaters are costumes -- they bring a commonality to an event and are an instant ice breaker," says Anne Marie Blackman, author of the book, Rock Your Ugly Christmas Sweater, and founder of My Ugly Christmas Sweater Inc., an online source for retro and modern holiday sweaters and dresses.

Mike Golomb, who opened his own online Ugly Sweater Store six years ago after he couldn’t find one in time for a holiday party, said he had little competition at first. Now, he says, the market has “basically exploded.” His customers range in age from 18 to 70, and have included bank executives, TV sports newscasters, members of the U.S. military, and professional ice hockey players. This year, he added men's ugly sweater suits -- polyester jackets and pants bedecked with Christmas trees and snowmen -- to his inventory (the snowmen line had already sold out by late November). He also sells ugly sweater leggings, wine bottle covers, and trophies that are as garish as the ugliest sweaters to which they are awarded.

Retail chains like Walmart and Target offer their own versions of the tacky pullover, as well as accessories like ugly sweater ties, ugly sweater drink koozies, and even ugly Hanukkah sweaters. Make-your-own ugly sweater kits that includes a sweater, stencils, felt and jingle bells are selling briskly this year at Nordstrom, Macy's and SkyMall

Ugly Christmas sweaters
Anne Marie Blackman (right), owns the My Ugly Christmas Sweater store.

Last year, Coke Zero joined the bandwagon with a contest inviting fans to design their own ugly Christmas sweater online using an "interactive sweater generator." The 100 sweaters that drew the most votes on social media were actually hand-stitched and shipped to the winners.

The Christmas sweater phenomenon started in the 1980s, but had a rebirth starting around 2008 when college-age kids started hosting ugly Christmas sweater-themed parties. "They wore Mom's or Grandmom's old sweaters as a goof," Blackman explains. Since then, the demographics have changed, and now all ages are embracing the holiday sweater-themed events, she adds.

Ugly Christmas sweaters
Best Ugly Sweater trophies for parties are big sellers.

A party is also what inspired Brand Castle founder Jimmy Zeilinger to add ugly sweater cookies to his company's line of craft cooking kits. He already offered dozens of novelty themes like Gingerbread Ninjas and Peanuts Great Pumpkin Patch, but Zeilinger was intrigued when a friend told him about an ugly Christmas sweater party he and his wife attended. 

"I thought, 'hey, maybe we could do that as a cookie'," he says.

The kit, which includes candy canes, rainbow non-pareils, and snowflake sprinkles, is one of the company's top 10 best-selling kits. “It sells itself,” Zeilinger says.

Don't expect the trend to fade anytime soon, observers say. Besides ugly sweater parties, there are ugly sweater bar crawls and ugly sweater 5K runs in at least 21 cities this month. In a sign of the times, a former NASA engineer even created a wearable tech ugly Christmas sweater.

Sold by London-based Morphsuits, the sweater allows wearers to insert their smart phones into a Velcro pouch inside the sweaters. Then, using a free app for iOS and Android devices, continuous images show crackling Yule logs, a caroling Christmas cat, or a Santa with moving eyes.

There's endless room for creativity, Golomb points out, because beauty is in the eye of the beholder. 

“What one person views as tacky is beautiful to others,” says Golomb, who recalls how his mother, a kindergarten teacher, once owned as many as 40 of the baubled sweaters. “That's what keeps this business fun.”