If the 500s were a dessert, it would be strawberry shortcake – sweet, but with substance. If it were a brand of shoe, it would be neon-colored Kangaroos with Velcro straps – fun, retro and suitable for dancing. If it were a video game, it would be “Mario Kart,” because if you have enough controllers, everyone can play. I could go on, but you get the idea.

The Portland-based trio makes happy, bouncy indie pop, utilizing just drums, guitar and keyboard to create a deceptively simple sound that’s as catchy as a cold in a third-grade classroom. It will play a holiday show at 7 p.m. Friday, Dec. 21, at the Keith Anderson Community Center in Orono, with a bunch of fantastic Maine bands, including Rotundo Sealeg, Wood Burning Cat and the Rattlesnakes.

Jonathan Merrifield, Isaac Turner and Sammie (no last name, please) formed the 500s in mid-2006, with the explicit purpose of making pop music.

“Jonathan and I wanted to start a pop band. We got Sammie to play with us, who had never played music before. We wrote the names of the notes on the keys for him,” said Turner, who plays guitar. “We’re really into indie pop from the ’90s. We’re big fans of bands like Tullycraft, and newer bands like the Smittens and Scary Monsters,” both of whom the band played with recently at Pop Fest New England, an indie pop festival held every November in Northhampton, Mass.

The 500s eschew any kind of pretension or attitude in their music. In other words, they just want to have fun, plain and simple. Who cares if you don’t know music theory, or if you feel like a big dork? Come out and play anyway!

“I’ve known pretty clearly all along what kind of band I didn’t want to be in,” said Merrifield. “I think [sometimes people feel like] music is unapproachable and hard to make. I wanted to make something inviting for other people, something that people could join in on. That’s why I like Kimya Dawson [an indie songwriter]. She really has that spirit of ‘come and play music.’ It doesn’t matter if it’s terrific or interesting to anyone, just come and play.”

That spirit of inclusiveness and do-it-yourself approach to making music is reflected in both the band’s 2007 EP, “OMG! OMG! OMG! The 500s! WTF?” and in its many intimate shows held at Strange Maine, a Portland record and vintage shop and music venue. Live, the band members wear matching T-shirts emblazoned with their names on the back, kind of like a recreation department softball team.

“The thing with the T-shirts and stuff is that there’s a whole visual aspect to being a rock band that I feel like a lot of people don’t take advantage of,” said Turner. “There’s a lot you can do visually, like having outfits and cool instruments. It keeps it entertaining.”

As if the band wasn’t endearingly silly enough, the 500s is the kind of band that, instead of taking promo pictures in, say, an abandoned lot or in a pastoral-looking field somewhere, it goes to a portrait studio. With their fuzzy sweaters. And the laser beam backgrounds.

“We recently went to the Sears portrait studio to be photographed together,” said Turner. “We have a friend who works there who got really excited, and apparently the staff was all abuzz about our arrival. We had a really fun photo shoot. And yes, we are having Christmas cards made with them.”

But don’t think that the 500s is just a bunch of goofballs. As far as the band may be from cooler-than-thou brooding rockers, it is, in fact, a really, really good band that writes some killer pop songs.

“It’s important not to take things too seriously, and not take yourself too seriously. We only take the music seriously,” said Merrifield.

The 500s, Rotundo Sealeg, Wood Burning Cat and the Rattlesnakes will play on Friday, Dec. 21, at the Keith Anderson Community Center in Orono. Admission is $5, and doors open at 7 p.m. For more information, visit www.myspace.com/the500s. Emily Burnham can be reached at eburnham@bangordailynews.net.