What do Legos, standardized testing, online museums and robots have in common?

Well, for one, there’s the GeekDad blog on Wired.com. Originally the brainchild of Wired.com Editor-in-Chief Chris Anderson in March 2007, GeekDad has since become one of the most popular blogs on the site. (See our recent post on Wired.com for more of the history of the GeekDad blog)

By day, the current editor of GeekDad (since September 2007), Ken Denmead, is a civil engineer. He described himself as “very much a geek and very much a father.” By combining these interests to create the tone of the blog, Denmead said, “I’ve tried to turn it into the Wired.com parenting blog.”

Denmeads sons, 11-year-old Eli and nine-year-old Quinn, have enjoyed some of the perks of their dad’s online moonlighting gig, and Denmead has learned some things from his kids. He often receives free, sample video games from companies who want their products reviewed on the blog.

“I won’t necessarily play them completely myself,” Denmead said. “I’ll throw ‘em to the kids and say, ‘Hey, play this, and then let me sit with you while you play it, and you tell me how you feel about it while you’re playing.’”

As a result, both the parent’s and the kids’ perspectives are reflected in the blog post — and Denmead gets to spend some quality game-playing time with his sons. Eli and Quinn aren’t complaining.

“A new game for the Wii or the DS shows up every couple of weeks, so they’re happy about that,” he said.

GeekDad contributor Matt Blum, a software engineer, also finds inspiration for posts from his kids. Blum has a six-year-old daughter and an eight-year-old son. One day, when the whole family was in the car, Blum’s daughter asked where the first human beings came from.

“My wife and I are both staunch believers in evolution,” Blum said, and so his daughter’s question led to a discussion of evolution. “I wrote a post about that because it’s a tough question. We weren’t prepared for her to ask that sort of question.”

The comments from GeekDad readers, some with similar beliefs and some with different ones, continued the discussion online. Denmead said that the interaction with readers has contributed to the popularity of the blog — which averages 20,000 to 22,000 hits per day. He uses Google analytics to gauge the traffic.

“One of the weird things about GeekDad within the larger Wired universe is that we really do speak more directly to our readers as sort of a personal conversation, whereas most of the rest of Wired is much more about posting news articles,” he said.

In order to increase posts’ visibility on the Wired.com main page, Denmead encourages the bloggers to vary the tone of the posts between conversational and more formal news reporting because the latter have a better chance of being featured on the main website. This kind of publicity draws readers to the blog.

“It’s been a lesson in journalism and in good writing for publication,” Denmead said.

Still, the driving force of GeekDad is its awareness of its audience. Blum has utilized his readers’ knowledge when preparing questions for interviews. He has asked readers to respond via Twitter with questions they’d like to ask a particular interview subject, such as Adam Savage of the Discovery Channel’s MythBusters.

“He does tons of interviews, so I didn’t want to ask him the same questions that everybody had already asked him, because what’s the point” Blum said about interviewing Savage.

To avoid duplicating previously published information, Blum does his own research prior to interviews and said that the readers’ contributions are also helpful.

“I figure if I’m asking the readers,” he said, “not only are they helping me, but that way the end product will be that much more interesting to the readers because they’ve had some input into it.”

He said Twitter offers the perfect means of gathering information for this purpose.

For Denmead, his work as the GeekDad editor has blossomed into a book deal. He was approached by a literary agent and, after researching the agency to make sure it was legit, wrote a book proposal that got picked up by Penguin Viking. The book, which will probably be titled “The GeekDad Book,” is a collection of “geeky” projects that parents can do with their kids.

The test group for these projects? Denmead’s sons Eli and Quinn, of course. The book is scheduled to come out around Father’s Day in 2010.

This kind of family-oriented material is largely what makes the GeekDad blog so easy for its readers to relate to.

“It is very much the nature of GeekDad to try and be a community blog,” Denmead said.

All of the bloggers are unpaid and write from different parts of the country (and the world—one author lives in Australia), which provides the blog with varied and fresh perspectives. The bloggers clearly share one thing in common with each other and with their readers.

“We are literally what the title is,” he said. “We are geek dads — and a couple of geek moms.”