David Sapers is known as the Sugar Daddy, and this guy has the goods to back it up. Sapers is the founder of Sugar Heaven, the vibrant candy store that blasts popular music from the 1960s, ‘70s, and ‘80s onto Newbury Street until midnight every day of the week. Walking into the store is like stepping into Candy Land: the line of customers winds from the counter back to the M&M dispenser and stretches past the table of Airheads, Chupa Chup lollipops, and old-fashioned taffy to the wall of Pez dispensers. Behind that, the blue sky-and-cloud-covered ceiling gives way to a rainbow arch that leads into a room where bulk candy bins cover the walls – chocolate on one side and gummies on the other. In the middle, a vivid hot-air balloon pokes through a table of European specialties.

Sapers founded Sugar Heaven in the middle of 2003, the year of the Atkins Diet, at a time when more and more Americans turned health-consciousness into a strict avoidance of carbohydrates and sugars. Industry-wide candy sales were down, and the fast-rising, sugar-phobic South Beach Diet didn't help the slide. Despite the continuing sweetless trend, Sapers' store just celebrated two years of steady customers. He opened a Sugar Heaven in Montreal five months ago and plans to open stores in Las Vegas , New Jersey , Natick , and, appropriately, South Beach in the near future. It seems that even Dr. Atkins can't compete with the cartoon-like funhouse that is Sugar Heaven – with its bright colors, peppy employees, and varied stock, Sapers is creating an image meant to draw customers of all ages.

A few years ago, Sapers and his girlfriend were looking for a 3-a.m. snack in Toronto and wandered into a local candy store. Sapers, a Back Bay/Cambridge real estate developer, knew there were few places for quality late-night snacks and even fewer for non-gourmet candy in the Boston area, so he drew up a plan and found space on Newbury Street , where he says “there's really no competition.” In fact, the only other candy store in the area is Teuscher Chocolates of Switzerland, a high-end gourmet chocolatier, and with Sugar Heaven's candy necklaces and chocolate-covered gummy bears, the two stores are hardly rivaling for the same audience. For the club and bar crowds, Sugar Heaven keeps its doors open until 12 a.m. every night, much later than most area businesses.

When designing the store, Sapers aimed for cleanliness, safety, interaction, and, most importantly, fun. All of the bulk candy, from offbeat treats like gummy sets of teeth and chocolate babies to the more familiar gumballs and chocolate-covered raisins, is displayed in clear gravity bins with doors to keep it fresh. To prevent customers from dipping their hands into the bins, employees offer free samples and provide bags and scoops. The bright walls, toy decorations, and signs indicating which staff member adores which candy keep customers busy looking as well as tasting. Much of the candy is interactive: the employees spin fresh cotton candy behind the counter and customers can make their own Pixy Stix, M&M, or jelly bean mixtures in dozens of color and flavor combinations.

To make this interaction fun, Sapers maintains a staff of 17 friendly, outgoing employees who match the party-like atmosphere of the store. They aren't afraid to dress in bold colors, chunky accessories, and funky hairstyles, drawing on the vivid atmosphere of the store itself. Many of his workers – who are predominantly college-age females – are recruited from local art schools.

“Their whole demeanor is different,” Sapers says of his artistic staff. “They're just very friendly and outgoing people.”

Whitney Gambrill, an 18-year-old Northeastern University student, started work at Sugar Heaven after her dormitory's resident advisor, another store employee, told her that her personality would fit in well. That peppy, friendly, talkative personality got her hired, and in her two weeks at Sugar Heaven, she has been put to work talking to customers and handing out balloons on the sidewalk in front of the store.

“It's not boring like other jobs,” she says. “You're involved, not just standing around. We share ideas, and it's a lot like a family – very welcoming.”

Like Willy Wonka's edible Chocolate Room, Sugar Heaven has a little bit of something for everyone. Sapers works with more than 190 vendors and carries confectionary items as well as candy-related novelties like Pez dispensers and nostalgia including a tin Wonder Woman phone-and-address book. More off-color stock hits include male and female candy underwear, which are displayed on a high shelf but still induce one young girl to run to her mother and whisper proudly, “Mommy, I saw candy undies!”

“We try to search anywhere in the world to get unique things,” Sapers says, indicating his popular line of European and Canadian chocolates.

Young customers can find the board game Candy Land, lollipops, and Pop Rocks, while older browsers might be more interested in throwback treats such as Bit-O-Honeys and Mary Janes. In front of the wall of nostalgic candies, 49-year-old John Hess chooses a green-and-white-marbled bouncy ball out of a bucket and pitches it at the floor. Catching it, he tells his wife, “I feel like a kid in a candy shop!” and laughs. This is Hess' first time in Sugar Heaven, and he says the store's atmosphere, coupled with the outgoing employees camped on the sidewalk with coupons and balloons, drew him in.

“This is the type of stuff you don't see everywhere,” he says, pointing to a bucket of Charleston Chews. “It's the kind of candy I saw when I was a kid.”

Maria Negri, a student at Berklee College of Music and Assistant Manager at Sugar Heaven, calls the store a time capsule.

“We get kids from age four when they get their first lollipop to the grandparents who love licorice, old-school candies, classic candies,” she says. “It really covers everyone…And no one I know ever gets sick of candy.”

Within this large clientele range, Sapers says most of his customers are women between the ages of 16 and 40. He doesn't know why, but jokingly supposes, “Maybe men drive women to eat candy?” It seems like a viable guess, considering that PMS Mints are among the store's most popular products. This also seems like the age and gender bracket that would be most attracted to the Atkins and South Beach diets, but Sapers says he hasn't had any difficulties with them. When the diet was at its height, he brought in Atkins-friendly candies, but they sold poorly even after he lowered prices.

“No one cared,” he says. “People come in, they know what they want, and they see things they've never seen before and they buy those, but they're not concerned [with low-sugar diets].”

Sapers seems to have gotten lucky by avoiding the food-industry crisis, but he has his bases covered even if candy sales do slow. In addition to in-store and online sales, Sugar Heaven hosts birthday parties in the store and caters weddings, bar mitzvahs, and other events including a recent bash for the Big Dig. He doesn't know of any other candy shops that cater, but he says the idea to branch out to corporate events, college parties, and more “just seemed like a good fit.”

It may seem surprising, but Sugar Daddy Sapers says that of all the colorful varieties of sweets in Sugar Heaven, his favorite is the good old peanut M&M. And like his taste in candies, the bigger his store gets, the more it all seems to come back to the basics – in this case, a fun atmosphere filled with friendly, dedicated employees.

“People come in here and they know that they're going to have music blasting and excitement and colors and vibrancy and they're going to see things they haven't seen since they were kids,” he says. “They always know they'll have fun.”

And as he smiles in his office, there's a young woman outside by the gummy fruit slices dancing wildly to the B-52s' “Rock Lobster.”