Since its release stateside last April, the $89 title, which ships packaged with the Wii Balance Board (a scale-like accessory that players can stand or rest on to perform exercises like yoga poses and push-ups), has rocketed up the sales charts, where it has remained a regular every month. "The appeal of Wii Fit is so broad and its ability to keep attracting new users every month has really played out time and time again," says Cammie Dunaway, Nintendo's executive vice president of sales and marketing, about the phenomenon.

Wii Fit sales have surpassed competing Wii efforts like Super Smash Bros. Brawl and Super Mario Galaxy. They've blown by any individual Madden or Guitar Hero games. They've even eclipsed the likes of epic successes such as Call of Duty: Modern Warfare and yes, Halo 1, 2 and 3. Dunaway believes Nintendo's runaway hit is so successful because it entices both old and new gamers. "I really think it's been about the breadth of appeal and changing the way that people think about videogames," she says. "So, for long time players like yourself, I think there's a real appreciation of what this represented as innovation in the category. And for non-gamers, it disrupted a perception that videogames aren't active."

wii-fit-20091012012501280.jpg
Eight million people are getting goofy in their living rooms.
Approximately 7.9 million copies of Wii Fit have been sold in North America through August, according to NPD. That puts the title in the upper echelon of videogame blockbusters alongside Rockstar's juggernaut Grand Theft Auto efforts. At the time of this writing, Wii Fit holds the third spot on the Top Five (capitalized for effect), which also houses Mario Kart Wii (at number five with 6.7 million) and Grand Theft Auto: Vice City (at number four with 6.9 million). Nintendo's high-priced and unconventional exercise program has already glided past one GTA game, but it's about to take down another: the monster-seller, San Andreas (currently at number two with 8.25 million).

"As your numbers show, with almost eight million sold life to date and a place in the Top 10 every month since it's launched, it's pretty clear that consumers love this game," says Dunaway. She's right. The package has enjoyed incredible staying power, clinging to the charts even when traditional software hits like, for example, Resident Evil 5, came and went. That said, the exercise alternative is not invulnerable, as an examination of month-to-month 2009 sales demonstrates. Wii Fit sales, which started off amazingly strong in January, have dropped considerably every month since.

Take a look at the pattern. In January, sales were at 777,000. In February, 644,000. In March, 541,000. In April, 471,000. In May, 352,000. In June, 271,000. In July, 164,000. And in August, 128,000.

Even with trail-off, the game continues to sell well -- and it'll almost certainly hit its next big benchmark when NPD releases the latest monthly estimates. "When we see the September sales, we think that's going to be strong and that'll put us over the eight million mark. And then with October, we'll just have to see," says Dunaway. Eight million copies of an $89 package. It's a huge win for Nintendo. But does Wi Fit still have enough muscle left to nudge past GTA: San Andreas for the number two spot? The answer would surely be yes if not for the impending release of Wii Fit Plus October 4, which effectively replaces the original bundle.

"Honestly, we have tried to get the market clean of Wii Fit because we want consumers to be exposed to the new product and eliminate any confusion in the market place. So it's really tough to predict what October numbers are going to look like," explains Dunaway. "There's certainly an opportunity there. That being said, we think Wii Fit Plus really expands upon the marketplace. And the new enhancements that come with Wii Fit Plus are going to make it appeal to an even broader audience."

Regardless of whether or not Wii Fit takes second or holds third on NPD's charts, it's clear that Nintendo has created a franchise that proves there really is an expanded audience willing to pay top dollar for something innovative. The first-party hopes Plus, with more exercises, mini-games and workout routines, will be enough to warrant the new $99 price tag -- when asked about the hike, Dunaway says, "Working out at the gym would be a lot more expensive than playing Wii Fit Plus."

And then what? Well, did we mention what the top-seller this decade was? With more than 11.1 million units sold through August, the answer is Wii Play, of course. It sold as a controller first and a piece of software second. Nintendo hasn't shied away from using peripherals to help sell its games, from the aforementioned Play to Link's Crossbow Training with the Zapper, Animal Crossing with WiiSpeak and, obviously, Wii Fit with the Balance Board. So what's next? It's called the Vitality Sensor and the company showed it very briefly at the Electronic Entertainment Expo 2009. President Satoru Iwata explained that the sensor will monitor your heart rate and allow for dynamic experiences based on your mood.

"I think that peripherals can really help expand the occasions for videogames," says Dunaway. "Certainly the Wii Vitality Sensor is going to enable us to keep innovating, to keep taking another step in expanding the appeal of videogames. So we're excited about having it launch. I'm excited. And will be excited to share more details with you down the road."