It is not a holiday like Christmas or Easter, religious in nature. But as secular holidays go, there aren’t many that put smiles on faces like Halloween. So big has Halloween grown over the last thirty years that, except for Christmas, it has become the country’s second most commercially successful ‘holiday.’

Halloween used to be province of the pre-teen crowd. But it has morphed into something well beyond kid’s stuff. “It’s an adult holiday,” says Cindy Catanese, owner of Disguises, one of the metro area’s largest and most sophisticated costume and make-up stores.

On Sunday, business had slowed quite a bit from the day before when space inside her West Colfax costume shop was at a premium. “Saturday was our biggest day,” she says, noting that the previous night was the season’s big party night for young adults. So busy was the last minute rush to pick out or pick up costumes that “you wouldn’t know it was a bad economy.”

In fact, Halloween has grown into a $6.8 billion dollar enterprise. According to the National Retail Federation, 161-million people will celebrate Halloween this year. “People are looking for an opportunity to have a little fun,” NRF’s Ellen Davis told CNN.

Of the nearly $7 billion spent on Halloween, more than two billion is spent on candy. Another $2.2 billion is spent on costumes for both children and adults with costumes averaging between $50 and $75. Amazingly, more than $300 million is spent on costumes for family pets.

“Competition is fierce,” Catanese says and customers are diverse. “Everyone likes Halloween.” The proprietor of Designs and former high school Spanish teacher says at least 40 percent of her business this year came from Latinos.

And while she loves the enthusiasm for the holiday, she is concerned that businesses like hers are threatened by ‘pop-up’ stands, temporary Halloween businesses selling cheap costumes. “Everyone is trying to get a piece of the Halloween pie.”

Haunted houses have also become one of the season’s biggest fright night economic engines. Most open for Halloween in late September or early October and charge an average of $20 a head, though in many places $40 will buy a ‘speed- pass, premium tickets that vault you to the front of the line. Even churches that once labeled Halloween as pagan are also getting into the act with offering Christian-themed denunciations of Halloween.

The rest of the multi-billion-dollar Halloween treasure is divided between home decorations, corn mazes and pumpkin patches.

Not surprisingly, this season’s most popular costumes are following the trend set by movies and television. Zombies and vampires are hot. Also big, a plus-sized Lady Gaga and Honey Boo-boo; Big Bird has flown off the racks.

But old-school never completely fades with either young or old. Broomfield seventh-grader, Lily, will be a devil this Halloween. She assembled her costume with a pastiche of thrift-store remnants costing a grand total of $30.

“People like to dress up like things they’ll never be,” says the 12-year-old honor student whose costume goes against form. She thought about dressing up as a dancer, something she actually does four days a week but, “it would have been too easy.”

And while this may be her last Halloween in costume for awhile, she still enjoys the trick-or-treat candy. “My favorite is Kit-Kat and then Junior Mints.” It is a haul, she says, she likes to share with her family’s non-trick-or-treater, her mother, Carla.