The magic returns: Harry Potter fans flock to purchase new book

A Ravenclaw, a Slytherin and a Hufflepuff walk into a bookstore. … It may seem like the beginning to a bad Harry Potter joke, but it's not.

Clad in wizard garb and T-shirts proudly supporting their Hogwarts houses, fans of the franchise on Saturday night did something they haven't done for almost a decade. They piled into the Union Square Barnes & Noble just before midnight to get their copy of "Harry Potter and the Cursed Child," the hotly anticipated continuation of J.K. Rowling's series.

Ahead of its release, the script book was the top preorder for Amazon and Barnes & Noble, a spot that was last held by "Harry Potter and the Deathly Hallows" in 2007.

"We absolutely expect this to be our number one selling book of the year," Mary Amicucci, chief merchandising officer at Barnes & Noble, told CNBC.

The ages of customers at the store on Saturday spanned the decades. Parents with children no older than 6 waited in line for animal balloons shaped like owls. Teenagers snapped pictures on their phones after getting "Harry Potter"-themed airbrushed tattoos and customers well into their 50s sat in the back rows of a magic show biding their time until midnight.

"We spent like three years reading them at night, every night before bed," Nora Levine said as her daughter sat at a table several feet away decorating a wooden wand with glitter and pompoms.

Beside Levine, Thomasina Forbes occasionally glanced back at the table to monitor the wand-making process, while she recounted how Harry Potter inspired her daughter to read other fantasy novels.

The sixth "Harry Potter" book came out when Forbes' first child was an infant. "I was nursing and reading at the same time," Forbes said. Her second child was born around the same time that the seventh book in the series was released.

Around the second grade, her children started reading the series with the incentive that, "when they finish one book, they can watch the movie," Forbes said.

"Can't watch the movie until we finish the book," Levine agreed.

The New York City Barnes & Noble location pulled out all the stops with four floors of "Harry Potter" activities for the young and young at heart. A live owl show, a trivia contest and a spelling bee are overshadowed by costume contest judged by a stern Severus Snape, a white-bearded Albus Dumbledore and three employees, including Amicucci. It is, perhaps, the biggest hit of the night, save for the main event, the unboxing of "The Cursed Child" at midnight.

"Nine years ago, we came to the seventh book midnight release right here," Amber Santiago, a self-proclaimed member of Ravenclaw house, told CNBC. "[Tonight] was a lot better. There were professors wandering around and we got pictures with all of them."

Her friend David Rodriguez, a member of Slytherin house, said he never expected to get another "Harry Potter" book. Instead, he believed that studios would be fighting to make remakes of the franchise films.

"I don't think any of us ever expected to have another 'Harry Potter' book," Barnes & Noble's Amicucci said. "I think that's probably been the biggest gift to all fans."