Oregon, Ill. ? That riding lawn mower may not look like much sitting in the back of the garage, crammed between bikes and shovels and rakes. Even when it’s out in the yard, puttering along, it seems more Forrest Gump than Mark Martin.

Strip off the cutting blades and give it room to run, though, and the tame gardening tool is transformed into a rumbling racer that can burn some serious sod. Capable of reaching speeds up to 90 mph, even NASCAR enthusiasts have to appreciate these “mowchines.”

“People think it’s just a lawn mower,” said Greg Honchell, whose mower of choice is a 1958 Springfield. “But it’s a true racing machine.”

Go ahead, snicker all you want. What started as a whim 13 years ago has grown so popular there are now more than 100 races a year all over the United States. The U.S. Lawn Mower Racing Assn. will have 14 points races this year, and local chapters run dozens more, including divisions for children 8-15.

The national championships are televised, and a video game is in the works. There’s no prize money, but some drivers have sponsors.

And that’s just in the United States. In England, where the sport began, they’ve been chewing up grass for more than 30 years.

“When I say I race lawn mowers, they look at you like, ‘You race lawn mowers? They only go three or four mph,'” said Ken Jones, the USLMRA’s race commissioner.

“When you start telling them about them, it’s like, ‘I’ve got to come watch that,'” Jones said. “To see the technology guys are taking from other racing forums and putting into mowers, it’s fascinating for people to see what they actually look like, how they sound and how fast they go.”

And they can go fast. Really fast.

Two of the USLMRA’s classes – IMOW and stock – are designed for the grassroots racer, with only slight modifications allowed to machines found in backyards across the country. The other divisions – BP, AP, SP and FX – are for drivers who crave speed.

Mowers in the BP category, for example, have engines with up to 20 horsepower, and their speeds typically reach 40-50 mph. FX (factory experimental) mowers would leave grass stains on those slowpokes in the right lane if they ever got on the open road.

“I’ve run 91 on a lawn mower,” said George Herrin, the USLMRA’s driver of the year last year. “(Another race) I averaged 70 miles per hour. That put me running about 89 on the straightaways.”

And that mower? Had to be some souped-up special that doesn’t resemble anything sold at the local hardware store, right? Nope. All mowers have to be originally designed to cut residential lawns and sold first through a dealer.

“I cut grass with that mower before I raced it. Six acres,” Herrin said. “It was a really good grass cutter. But I needed the chassis.”

That’s the kind of practicality that got this sport mowing in the first place.

Back in 1973, some racing fans were sitting in a British pub, complaining about the high cost of motor sports. Whether it was cars, go-karts or motorcycles, the average fan was being priced out of participating in the sport.

U.S. Lawn Mower Racing Assn.

British Lawn Mower Racing Assn.

According to the British Lawn Mower Racing Assn.’s Web site, somebody in the group said, “Everybody has a lawn mower. Let’s race those.” And cutting the grass never was quite the same.

In 1992, Chicago-based Gold Eagle Co. was looking for a new way to market one of its products, STA-BIL Fuel Stabilizer, and heard about the English lawn mower racers. Thinking it might be a fun promotion, it announced the formation of the USLMRA on April Fool’s Day.

“It started off as a promotional gimmick,” said Jones, the USLMRA’s race commissioner, “and each year it’s kept growing.”

But, obvious giggle factor aside, why?

For racing enthusiasts, it’s an affordable way to get their fix. While some will spend $5,000 to $10,000 a year on their mowers, others get by with as little as $500. Most people already own a mower, and getting it ready for the stock division can be as simple as removing the cutting blades and having an automatic turnoff switch.

Don’t have a mower? Take a leisurely drive in the country or more rural suburbs and scout out those roadside junk piles. There’s bound to be a mower or two buried in there.

The only other requirement is safety gear: helmet; goggles or a face mask; long-sleeve shirt or jacket; long pants; full-finger gloves, and leather footwear that covers the ankle. While some drivers at Sunday’s Ogle County Fair Mowdown were decked out in racing suits and shoes, motocross chest protectors and color-coordinated helmets, others looked like they’d taken a wrong turn out of their yards in jeans, T-shirts and work boots.

“You really don’t have to spend any more than you want,” said Chris Macri, president of the Ohio Lawn Mower Racing Assn. “It really depends on how fast and how good looking you want to be.”

And, as anyone who’s had to take a spin or two around the yard knows, lawn mower racing is for just about anybody who is interested. Short, tall, big, small, male, female – as long as you can step on the gas and steer, you can race.

Chris Matuschka of East Leroy, Mich., never had raced anything – “except on foot” – until he saw a movie about lawn mower racing on the Discovery Channel in 2003. Last Sunday, he raced in three classes and had top-five finishes in all of them, including a victory in the IMOW division.

“It’s something everybody can do, but it’s unique,” said Honchell, from Urbana, Ohio. “It’s different than cars, it’s different than go-karts. It’s still serious racing, but it sets it apart.”

The races, usually held on dirt or grass tracks lined with hay bales, look like any other in motor sports. Attendance is mandatory at the pre-race drivers’ meeting and practice, and no mower gets on the track until it has passed a safety inspection.

With a call of “On your mark, get set, MOW!” drivers race across the track and jump on their mowers. Bumping is prohibited, but the jostling and jockeying for position would make the NASCAR folks proud.

“I never knew this existed until today,” said Robert Thompson, who was at Sunday’s race with his wife after reading about it in the paper. “(I thought) ‘What idiot wants to get on a lawn mower and race?’ … But this is one of the coolest things I’ve seen.”

Thompson isn’t the first to question the racers’ sanity. They take plenty of ribbing from friends and co-workers – one driver was asked if he raced llamas – but they’re too busy enjoying themselves to care.

They trade tools, parts and tips, and help each other with their mowers. They swap grass and mowing puns, and come up with nicknames like Sodzilla, Mr. Mowjangles and The Prograsstinator.

“It’s a passion,” Herrin said. “Unless you do it, you can’t describe it. It doesn’t justify it.”

Still, even Herrin was amazed to get an e-mail a while back from a fan in England who wanted his autograph.

“Because I race lawn mowers?” Herrin said. “How cool is that?”